ephedroids from the Early Cretaceous Yixian Formation in Liaoning ...

Pl. Syst. Evol. 262: 239–265 (2006) 

DOI 10.1007/s00606-006-0481-2 

Liaoxia Cao et S.Q. Wu (Gnetales): ephedroids from the Early 

Cretaceous Yixian Formation in Liaoning, northeastern China 

C. Rydin 1 ,S.Q.Wu 2 , and E. M. Friis 1 

1 Swedish Museum of Natural History, Department of Palaeobotany, Stockholm, Sweden 

2 Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China 

Received April 25, 2006; accepted July 24, 2006 

Published online: December 1, 2006 

Ó Springer-Verlag 2006 

Abstract. Gnetalean compression-impression fossils 

are described from the Early Cretaceous Yixian 

Formation, Liaoning Province, north-eastern 

China, and assigned to six species of Liaoxia Cao 

et S.Q. Wu. The fossils have opposite-decussate 

phyllotaxis and cones comprising 2–12 pairs of 

bracts. Ovulate cones have seeds typically in a 

distal position. The species differ from each other 

and from previously described fossils in the absence 

or presence of leaves, shape of cones and seeds, and 

shape and position of cone bracts. The species of 

Liaoxia are probably close relatives of extant 

species of Ephedra L., but diagnostic reproductive 

details that could confirm this hypothesis are not 

preserved. The restricted information in the fossils 

and the poorly understood morphological diversity 

of extant Ephedra, prevent assignment of the fossils 

to any particular subgroup of Ephedra, as well as 

an explicit exclusion of them from the extant genus. 

Key words: Ephedra, Liaoxia, Gnetales, Yixian 

Formation, fossils, Early Cretaceous, China, Jehol 

Biota. 

Gnetales are a small group of seed plants with 

about 65–75 species in three genera (Kubitzki 

1990). Gross morphology is uniform within 

each genus (Ephedra L., Gnetum L. and the 

monotypic Welwitschia Hook. f.), but differs 

significantly between the genera and there is 

also significant ecological divergence between 

the genera with representatives in deserts 

(Welwitschia), semiarid habitats (Ephedra) 

and tropical rain forests (Gnetum). Based on 

these data, and the scattered geographic distribution 

of the group, it has been suggested 

that the Gnetales are ancient with a large 

extinct diversity (e.g. Arber and Parkin 1908). 

Fossil support for a relictual status of the 

group has mainly come from isolated pollen 

(Wilson 1962, Traverse 1988, Crane and 

Lidgard 1989, Osborn et al. 1993, Crane 

1996), but recent findings of mega- and 

mesofossils from Lower Cretaceous strata of 

Asia, Australia, Europe and North and South 

America, with vegetative and reproductive 

details preserved, show that the group was 

diverse and widespread already in the Early 

Cretaceous. 

Many of the Early Cretaceous gnetalean 

megafossils are ephedroid with striate stems, 

more or less reduced leaves, and opposite and 

decussate phyllotaxis. Such fossils have been 

reported from China (Wu et al. 1986, Cao et 

al. 1998, Guo and Wu 2000, Sun et al. 2001, 

Tao and Yang 2003, Yang et al. 2005), central 

Asia (Krassilov 1982, Krassilov and Bugdaeva

240 C. Rydin et al.: Cretaceous ephedroids from China 

1982) and from Australia (Krassilov et al. 

1998). There are also many undescribed specimens 

from China and Brazil (see e.g. Wu et al. 

2000, Mohr et al. 2004). Early Cretaceous 

mesofossils include coalified seeds with unique 

Ephedra characters such as a sclerenchymatic 

seed envelope with apical papillae, and in situ 

polyplicate pollen (Rydin et al. 2004, Rydin et 

al. 2006). 

In addition to the ephedroid fossils there 

are also a few Early Cretaceous megafossils 

that may represent the Welwitschia-Gnetum 

clade (Crane and Upchurch 1987, Rydin et al. 

2003, Dilcher et al. 2005, Rydin et al unpubl. 

data), as well as several gnetalean fossils that 

are difficult to assign to any of the extant 

lineages (e.g. Krassilov 1982, Krassilov and 

Bugdaeva 1982, Krassilov 1986, Krassilov and 

Bugdaeva 1988, Duan 1998, Sun et al. 2001). 

Further, dispersed seeds and pollen assigned to 

the extinct order Erdtmanithecales (Pedersen 

et al. 1989, Friis and Pedersen 1996, Kvaček 

and Pacltová 2001) are probably related to 

Gnetales, but the vegetative morphology of 

these plants is unknown. 

Pre-Cretaceous evidence of the Gnetales 

are mainly dispersed polyplicate ephedroid 

pollen (e.g. Wilson 1962), but there are also 

several records of megafossils that probably 

belong to the Gnetales, for instance Ephedrites 

sinensis Wu et al. and E. exhibens Wu et al. 

from Early Jurassic deposits in Qinghai, China 

(Wu et al. 1986). However, most pre-Cretaceous 

gnetalean megafossils are difficult to 

interpret. The Permian cone Palaeognetaleana 

auspicia Wang with in situ polyplicate pollen 

(Wang 2004), the Late Triassic plant Dechellyia 

gormani Ash (Ash 1972), and the 

Jurassic Ust-Balej fossils of East Siberia 

(Krassilov and Bugdaeva 1988), are all examples 

of fossils that have been discussed as 

putative Gnetales, but for which a precise 

systematic affinity remains to be established. 

In this study we describe a number of 

ephedroid fossils from the Liaoning province 

of northeastern China collected in sediments of 

the Yixian Formation. The Yixian Formation 

and the overlaying Jiufotang Formation com- 

prise the Jehol Group, famous for its exceptionally 

rich biota, which include exquisitely 

preserved invertebrates, osteichthyan fish, 

amphibians, mammals and reptiles including 

feathered dinosaurs and early birds (Chang 

et al. 2003). Vigorous collisions of plates in the 

western rim of the Pacific resulted in intensive 

volcanic activity (Wang et al. 1983) during the 

deposition of the Yixian Formation and ash 

falls repeatedly entombed organisms present in 

the area and effectively prevented scavenging 

and bacterial decay. The immediate anoxic 

conditions provided by the volcanic ash tuffs 

permitted the preservation of original softtissue 

features and stomach contents (Chen 

et al. 1998, Zhou and Zhang 2002); even 

questions on the physiology of Cretaceous 

vertebrates and of plant-animal interactions 

can be addressed (Zhou et al., 2003, and 

papers in Chang et al. 2003). 

In contrast to the anatomical preservation 

of many animals of the Jehol Biota, plant 

fossils rarely have cellular details intact. Similar 

to the slightly younger Crato plants of 

Brazil, the Jehol plants are compression or 

impression fossils, often with various organs 

such as stems, leaves and reproductive structures 

still attached. In rare cases even whole 

plants are preserved providing excellent information 

on gross morphology. Anatomical 

features, however, are rarely preserved (e.g. 

Wu 1999, Sun et al. 2001, Chang et al. 2003, 

Friis et al. 2003, Leng and Friis 2003) and 

tissues are often replaced or filled in with pyrite 

framboids and microcrystallines (Leng and 

Yang 2003). 

The Jehol flora comprises a diverse assemblage 

of bryophytes, lycopods, sphenopsids, 

ferns and various seed plants including many 

conifers and rare angiosperms (Sun et al. 1998, 

Wu 1999, Sun et al. 2001, Sun et al. 2002, Leng 

and Friis 2003, Leng et al. 2003, Wu 2003). 

Fossils assignable to the Gnetales (Wu 1999, 

Sun et al. 2001, Wu 2003) also show some 

diversity and include plants described as 

Liaoxia chenii Cao et Wu and Eragrosites 

changii Cao et Wu (Cao et al. 1998), Chaoyangia 

liangii (Duan 1998, later synonym of

C. Rydin et al.: Cretaceous ephedroids from China 241 

Gurvanella Krassilov 1982), Ephedrites? elegans 

Sun et Zheng (Sun et al. 2001), and 

Ephedra archaeorhytidosperma (Yang et al. 

2005). Dispersed ephedroid pollen are reported 

to be rare in the Yixian Formation (Li and Liu 

1999, Li 2003), but include striate forms 

assigned to Ephedripites and the Welwitschialike 

Jugella. The fossils described here are 

similar to extant Ephedra in gross morphology, 

but they usually lack anatomical details and 

cannot be assigned unambiguously to extant 

Ephedra. The genus Ephedrites Go¨ppert et 

Berendt is unsuitable for gnetalean fossils and 

we have therefore referred the Jehol ephedroids 

in this study to the genus Liaoxia Cao 

et Wu (Cao et al. 1998). 

Materials and methods 

The fossils are from two horizons in the Yixian 

Formation of Liaoning, northeastern China. The 

Yixian Formation comprises four beds (from base 

to top: Lujiatun Bed, Jianshangou Bed, Dawangzhangzi 

Bed, Jingangshan Bed). Specimens 

PB20717 – PB20720 are from layer seven of the 

Jianshangou Bed, in the Huangbanjigou section, 

Beipiao (latitude: 41° 37¢ north; longitude: 120° 50¢ 

east, see Chen et al. 2005) and specimens PB20721 – 

PB20726 are from layer two of the Dawangzhangzi 

Bed in the Fanzhangzi section, Lingyuan (appr. 

latitude: 41° 10¢ north; longitude: 119° 45¢ east, see 

Wang et al. 2000). The geology of the two sections 

is described by Wang et al. (2000) and Chen et al. 

(2005) (see also Chang et al. 2003). The age of the 

Yixian Formation has been much debated, but 

there is now general acceptance for a mid-Early 

Cretaceous age of the sequence (see Zhou et al. 

2003). Basal basalts and andesites of the Dawangzhangzi 

Bed have been dated to approximately 

122.5 Myr (Wang and Zhou 2003). 40 Ar- 39 Ar dates 

of approximately 125 Myr have been obtained 

from analyses of sanidine and biotite crystals from 

three different tuff layers in the Jianshangou Bed 

(Swisher et al. 1999, Swisher et al. 2002) and an 

40 39 

Ar- Ar date of 128 Myr has been obtained from 

basalt-andesite in the lowermost Lujiatun Bed 

(Wang et al. 2001). Later 40 Ar/ 39 Ar dating of the 

Lujiatun Bed suggest that this bed may be younger, 

approximately 123 Myr (He et al. 2006). The age of 

the base of the Yixian Formation (128–123 Myr) 

thus corresponds to Barremian age or possibly 

early Aptian according to the most recent International 

Geographic Chart (Gradstein et al. 2004). 

The Jehol plant fossils contain few or no 

anatomical details. They were studied using dissecting 

microscope. No attempts were made to do 

SEM. The characters of the fossils were documented 

by photography and compared with fossils 

in the literature. All specimens are located in the 

Nanjing Institute of Geology and Palaeontology, 

Chinese Academy of Sciences, China. 

Results 

Formal descriptions. Based on new informative 

specimens of Liaoxia chenii and other 

ephedroid fossils from the Yixian Formation 

an emended diagnosis of the genus Liaoxia is 

presented, and a new combination, Liaoxia 

changii, suggested. Further, four new species 

are described and assigned to Liaoxia (Liaoxia 

acutiformis, L. robusta, L. elongata, L. longibractea). 

Spermatophyta 

Order Gnetales 

Genus Liaoxia Cao et S.Q. Wu (emend. Rydin, 

S.Q. Wu et Friis). 

Emended generic diagnosis. Plants similar to 

extant Ephedra, with erect, striate stems, 

distinct and slightly swollen nodes, and opposite-decussate 

branching. Leaves linear or 

lacking. Reproductive structures forming 

cones, sessile to pedunculate, rounded to 

obovate to elongate in shape, consisting of 

opposite-decussate bracts. Seeds ovoid to elliptic 

in shape, positioned in axil of cone bracts. 

Specimens investigated: PB17800, PB17801, 

PB17802, PB17803, PB17804, PB20717, 

PB20718, PB20719, PB20720, PB20721, 

PB20722, PB20723, PB20724, PB20725, PB20726. 

Type species. Liaoxia chenii Cao et S.Q. 

Wu (emend. Rydin, S.Q. Wu et Friis) 

Synonyms and previously published material. 

1998 Liaoxia chenii Cao et S.Q. Wu — Cao et 

al., p. 231, plate I:1–2.


1999 Liaoxia chenii Cao et S.Q. Wu — Wu p. 

21, plate XIV:3, XV:3. 

2000 Ephedrites chenii (Cao et S.Q. Wu) Guo 

et X.W. Wu — Guo and Wu p. 86, plates I:1– 

4, II:1–4. 


et X.W. Wu — Sun et al. p. 206, plates 24:2, 

64:1, 3–6 (non plate 64:7–9). 

2003 Liaoxia chenii Cao et S.Q. Wu — Chang, 

p. 174, Fig. 241. 

Emended specific diagnosis. As for the 

genus with the following distinctions. Branches 

c. 0.5–3.0 mm wide, internodes 8–40 mm long. 

Leaves 5–20 mm long, with two parallel veins. 

Cones obovate, 4–10 mm long, 2–5 mm wide, 

with 2–6 pairs of bracts. Cone bracts ovate to 

triangular and reflexed, c. 4 mm long, with an 

acute to attenuate apex, two parallel veins. 

Seeds ovoid to elliptic, c. 1 mm long, c. 0.3– 

0.7 mm wide. 

Holotype. PB17800 (Fig. 1). 

Paratype. PB17801. 

Type locality. Near Chaomidian at Shangyuan 

Village of Beipiao, Liaoning, China. 

Stratigraphic position and age. Jianshangou 

Bed, Yixian Formation, Early Cretaceous 

(Barremian-early Aptian?). 

Comments on the type material. The holotype 

of Liaoxia chenii (PB17800, Cao et al. 

1998) (Fig. 1) is a reproductive shoot, c. 9 cm 

long. It is clearly ephedroid in gross-morphology 

with striate stems, 1–3 mm wide. Branching 

is opposite and decussate with distinct 

nodes. Internodes are 8–40 mm long. Leaves 

are linear, at least 20 mm long and c. 1–2 mm 

wide, probably with two parallel veins. Cones 

are 5–10 mm long and 3–4 mm wide, obovate 

with 2–6 pairs of reflexed cone bracts, c. 4 mm 

long, and ovate with an attenuate apex. Cone 

bracts have two parallel veins. 

Note that in the description of Ephedrites 

chenii in Sun et al. (2001), two additional 

specimens (plate 64, Figs. 7–9) are presented. 

These fossils may be ephedroid, but they lack 

features characterising Liaoxia and are not 

included here in the synonymy list of Liaoxia 

chenii. 

New material of Liaoxia chenii. Specimens 

PB20717–PB20718 (Figs. 2–4) from the Huangbanjigou 

Section, includes two compression 

fossils with oxidized organic material. The 

specimens show distinct features of Liaoxia 

chenii and are here included in this species. In 

one specimen the uppermost 5 cm of a 

branched plant, c. 13 cm wide, is preserved 

(Figs. 3–4). The other specimen is a detached 

apical part of a reproductive shoot, 2.5 cm 

long (Fig. 2). Stems are erect with 8–17 mm 

long internodes, longitudinally striate and 

2 mm wide in basal parts and 0.5 mm in upper 

parts, thicker at nodes. Phyllotaxis is opposite 

and decussate. Leaves are linear (Figs. 2–3), up 

to at least 7 mm long and 0.1–0.3 mm wide. 

Venation is indistinct, but there are apparently 

two parallel veins in each leaf. Cones are 

axillary at nodes or terminating branches, 

sessile or pedunculate, and obovate to elongate, 

4–7 mm long, 2.5–5 mm wide and with 

2–6 pairs of bracts. Cone bracts are delicate 

and with two veins (Fig. 3). They are narrowly 

ovate with an acute to attenuate apex, 3–4 mm 

long, about 0.8 mm wide at the base, 0.3 

towards the apex, decussately arranged and 

often reflexed to a position almost at a right 

angle to the cone axis. A few seeds are 

preserved in the axils of apical or distal cones 

bracts of some cones (indicated by an arrow in 

Fig. 3). They are ovoid and 0.9–1.1 mm long 

and 0.3–0.7 mm wide. No internal or external 

anatomical details are preserved. 

Liaoxia changii (Cao et S.Q. Wu) Rydin, 

S.Q. Wu et Friis comb. nov. 

Basionym. Eragrosites changii Cao et S.Q. 

Wu (Cao et al., February 1998. Chinese Sci. 

Bull. 43: p. 231, plate II:1–3). 

Synonyms and previously published material. 

1999 Liaoxia changii Cao et S.Q. Wu — Wu, p. 

21, plate XV:1, 4. 


et X.W. Wu — Guo et Wu p. 86, plates 1:5–7 

and 2:5–8.



et X.W. Wu — Sun et al. p. 206, plates 24:4, 

64:2. 

Emended specific diagnosis. As for the 

genus with the following distinctions. Branches 

c. 0.3–4.0 mm wide, internodes 8–40 mm long. 

Leaves absent. Cones elongate to obovate, 4– 

6 mm long, 1.5–3 mm wide, with 6–10 pairs of 

bracts. Cone bracts erect to slightly reflexed, 

2 mm long, with an acute to obtuse apex. 

Seeds ovoid, c. 1 mm long, c. 0.2–0.3 mm 

wide. 

Holotype. As for the basionym: PB17803 

(Fig. II:2, Cao et al. 1998). 

Paratypes. PB17802, PB17804 (Fig. 5) 

(Figs. II:1, 3, Cao et al. 1998). 

Type locality. Near Chaomidian at Shangyuan 

Village of Beipiao, Liaoning, China. 




Comments on the type material. The holotype 

(PB17803) and its counterpart (PB17804, 

Fig. 5) are poorly preserved impression fossils, 

consisting of several separate branches, not all 

in connection. Stems are striate, about 0.5– 

4.0 mm wide. Nodes are clearly set and slightly 

swollen separated by internodes, about 

8–40 mm long. Leaves are absent. Cones are 

pedunculate to sessile, 5–6 mm long, 2.5– 

3 mm wide. There are 6–10 pairs of bracts in 

each cone. Bracts are 2 mm long, with acute to 

obtuse apices. No seeds are preserved. Some 

cones have slightly reflexed cone bracts, which 

might indicate that they are female; others are 

more narrowly elongate with erect bracts. 

They may represent female cones in different 

stages of maturity or alternatively, there may 

be a mix of male and female branches on this 

slab. 

New material of Liaoxia changii. Specimen 

PB20722 (Figs. 6–8) from the Dawangzhangzi 

Bed at the Fanzhangzi Section is a female 

plant that in all characters is indistinguishable 

from the type specimen of Liaoxia changii 

described above, but is better preserved than 

the type material. The specimen has weakly 

striate stems with swollen nodes. Stems are 

0.7–1.7 mm wide with opposite and decussate 

branching and internodes about 10–18 mm. 

Leaves are absent (Fig. 6). Cones are slightly 

obovate to elongate, pedunculate to nearly 

sessile, 5–6 mm long and 2.5–3 mm wide 

(Fig. 8). Each cone has 6–10 pairs of erect to 

slightly reflexed bracts, 2 mm long, and with 

acute to obtuse apices. Impressions of seeds 

are observed in the axils of some bracts. Seeds 

are c. 0.8–1 mm long, 0.2–0.3 mm wide and 

ovoid. 

Liaoxia acutiformis Rydin, S.Q. Wu et Friis sp. 

nov. 

Specific diagnosis. As for the genus with the 

following distinctions. Branches 0.3–1.4 mm 

thick, leaves 2.7–7.0 mm long, 0.2 mm wide, 

probably with two parallel veins. Cones elongate 

(to narrowly obovate), 3.5–6.0 mm long, 

c.1.7–2.7 mm wide, with 6–12 pairs of bracts. 

Cone bracts erect to slightly reflexed, 1.5– 

2.0 mm long, narrowly ovate with acute apex, 

two parallel veins. 

Etymology. Named after the acute apex of 

the cone bracts. 

Holotype. PB20721 (Figs. 9–11). 

Locality. Fanzhangzi Section, Lingyuan, 

Liaoning, China. 

Stratigraphic position and age. Dawangzhangzi 

Bed, Yixian Formation, Early 

Cretaceous (Barremian-early Aptian?). 

Description and comments. The type material 

of Liaoxia acutiformis comprises one 

compression fossil of an ephedroid plant with 

sparse remains of oxidized organic material 

preserved (Fig. 9). No anatomical details are 

preserved. The shoot is 7 cm long with opposite 

and decussate branching. Stems are erect 

with weak impressions of longitudinal striations, 

internodes about 6–14 mm long, stems 

0.3–1.4 mm wide, thicker at nodes. Leaves are 

linear, and opposite at nodes, 2.7–7.0 mm long 

and c. 0.2 mm wide (Figs. 9–11). Indistinct 

remains of two veins are present in some leaves 

(Fig. 10). There are about seven elongate (to 

narrowly obovate) cones, 3.5–6 mm long, and


about 1.7–2.7 mm wide. Cones are sessile and 

placed axillary at nodes or terminally on 

branches. Each cone has between 6 and 12 

pairs of erect to slightly reflexed bracts that 

appear decussately arranged (Fig. 10). Bracts 

are narrow and ovate, 1.5–2.0 mm long, with 

an acute apex. Seeds or microsporangiate 

organs have not been observed. 

This fossil is similar to Liaoxia chenii in 

vegetative morphology, but the cones are more 

elongate in shape. Liaoxia acutiformis is further 

distinguished from L. chenii by having a higher 

number of bracts, probably up to 12 pairs, in 

each cone, in contrast to L. chenii that has 2–6 

pairs in each cone. The apex of the cone bracts 

differs in being acute to obtuse in L. acutiformis 

while it is acute to attenuate in L. chenii. 

Liaoxia elongata Rydin, S.Q. Wu et Friis sp. 

nov. 


following distinctions. Branches 0.4–1.5 mm 

thick, sometimes with multiple axillary nodes. 

Leaves absent. Cones narrowly elongate, 5– 

10 mm long, c. 2–3 mm wide, with 8–12 pairs 

of bracts. Cone bracts erect, 2.5–4 mm long, 

with an attenuate apex. 

Etymology. Named after the narrowly 

elongated cones. 

Holotype. PB20724 (Figs. 14–15). 

Paratype. PB20723 (Figs. 12–13). 






Description and comments. The holotype of 

Liaoxia elongata comprises the uppermost 

5.5 cm of the plant (Figs. 14–15). An additional 

specimen is a shoot with slightly larger 

structures, c. 4 cm long and 4 cm wide, repre- 

senting the central part of the plant (Figs. 12– 

13). No anatomical details are preserved. 

The stems are erect with nodes and internodes. 

Branching is opposite and the paratype 

has multiple axillary units (Fig. 12). Stems are 

0.4–1.5 mm thick, thicker towards the base 

and at nodes, and have very weak remnants of 

longitudinal striations. Leaves are absent. 

Cones are axillary at nodes or terminally on 

branches and may be sessile or pedunculate. 

They are narrowly elongate (Figs. 13–14) and 

vary in length between 5–6 mm in the holotype 

to 6–10 mm in the paratype, but are all 

2–3 mm wide. One cone on the paratype is 

smaller and rounded, c. 3 · 3 mm (arrow in 

Fig. 12). Each cone comprises 8–12 pairs of 

erect and decussately arranged bracts. The 

bracts are probably very narrowly ovate, c. 

2.5–4 mm long, with attenuate apex. Seeds or 

microsporangiate organs have not been 

observed. 

These plants are similar to Liaoxia changii 

(Cao et al. 1998) in the over all ephedroid 

habit, and the leaf-less stems, but differ from 

Liaoxia changii mainly in that they have 

cones with more bracts, which are erect and 

have a distinctly pointed, attenuate apex. The 

cone bracts of Liaoxia changii are slightly 

reflexed and have a less distinctly pointed, 

acute apex. 

Liaoxia robusta Rydin, S.Q. Wu et Friis sp. 

nov. 


following distinctions. Branches 1.5–2 mm 

thick, with multiple axillary units. Leaves at 

least 15–20 mm long, 0.5–1.0 mm wide. Cones 

obovate to elongate 7–16 mm long, c. 6–8 mm 

wide, with 4–10 pairs of bracts. Cone bracts 

reflexed, 4–7 mm long, ovate with acute to 

attenuate apex, one-two parallel veins. Seeds 

c 

Figs. 1–4. Liaoxia chenii Cao et S.Q. Wu (emend. Rydin, S.Q. Wu et Friis). 1 The holotype of Liaoxia chenii 

(PB17800). 2 New specimen (PB20718); the detached apical part of a reproductive shoot. 3–4 New specimen 

(PB20717); the uppermost part of a branched plant. Note the seed and the thin leaf indicated by arrows in 

Fig. 3. Scale bars = 1 cm in Figs. 1, 2, 4; 0.3 cm in Fig. 3. S = seed; L =leaf

C. Rydin et al.: Cretaceous ephedroids from China 245


rounded, elliptic, 2.5–3.5 mm long, 1.2–2 mm 

wide. 

Etymology. From the robust morphology 

of the plant. 

Holotype. PB20719. (Figs. 16, 18). 

Paratype. (Counterpart) PB20720. (Fig. 17). 

Locality. Huangbanjigou Section, Beipiao, 






of Liaoxia robusta comprises two compression 

fossils of an ephedroid, female plant, 

part and counterpart, with oxidized organic 

material preserved. The shoot is 17 cm long 

(Fig. 16), but on the counterpart, only the 

uppermost 8 cm are preserved (Fig. 17). No 

internal or external anatomical details are 

preserved. Precipitations surround the plant 

remains and make stems and leaves appear 

wider than they are. 

Stems are erect with nodes and internodes, 

1.5–2 mm thick, thicker at nodes, and have 

longitudinal striations-ridges. Phyllotaxis is 

opposite and decussate with multiple axillary 

units. Leaves are linear, 15–20 mm long and 

appear 1.5–2 mm wide, but the width also 

comprises precipitates and the leaves were 

probably only 0.5–1 mm wide. Indistinct 

remains of three or four veins are present on 

some leaves. The plant has about 15 ovulate 

cones that are rounded to ellipsoid in longitudinal 

outline. Cones vary in length between 7 

and 16 mm, but are all about 6–8 mm wide, 

sessile or pedunculate, and are positioned 

axillary at nodes or terminally on branches. 

Cones comprise between approximately 4 and 

10 pairs of reflexed and decussately arranged 

bracts. The bracts are ovate, 4–7 mm long, 

with a long and acute to attenuate apex. Seeds 

are rounded to elliptic, 2.5–3.5 mm long and 

1.2–2 mm wide, but no cell structures or other 

anatomical details are preserved. There is one 

seed in the axil of all cone bracts, including 

proximal bracts. 

This plant differs from other species of 

Liaoxia in that all features are larger. Further, 

it has multiple axillary branching, which has 

otherwise only been observed for Liaoxia 

elongata and L. longibractea, and these species 

are clearly different from L. robusta in the 

characters of the cones. Liaoxia robusta differs 

from Ephedra in the presence of seeds in the 

axil of all bracts, not only in distal pairs as in 

extant Ephedra. 

A detached winged seed occurs in close 

association with Liaoxia robusta (Fig. 18). 

The seed body of this isolated seed is of 

approximately the same length as the in situ 

seeds and the possibility that it originates 

from a Liaoxia cone cannot be ruled out, but 

the shape of the seed and the nature of the 

wing suggest that it was more likely produced 

by one of the conifers reported for the Yixian 

Formation. 

Liaoxia longibractea Rydin, S.Q. Wu et Friis 

sp. nov. 


following distinctions. Branches c. 1.5 mm 

wide, with multiple axillary branching. Cones 

sessile to very shortly pedunculate, rounded, 

3.5–4 mm long ()15 mm including bract 

apex), c. 2–3 mm wide, with 1–2 pairs of 

bracts. Cone bracts reflexed, 10–15 mm long, 

extended with a setose apex, two parallel 

veins. Seeds elliptic, 2.5–4.0 mm long, c. 

1 mm wide. 

Etymology. Named after the very long and 

narrowly extended cone bracts. 

Holotype. PB20725 (Fig. 19). 

Paratype. PB20726 (the counterpart, 

Fig. 20). 







of Liaoxia longibractea comprises two 

relatively well-preserved compression fossils 

(part and counterpart) with small amounts of 

oxidized organic material preserved. No internal 

or external anatomical details are pre-


Figs. 5–8. Liaoxia changii (Cao et S.Q. Wu) Rydin, S.Q. Wu et Friis comb. nov. 5 The counterpart of the 

holotype (PB17804). 6–8 New specimen (PB20722); a relatively well-preserved fossil with seeds in the axil of 

cone bracts. Leaves are absent in Liaoxia changii. Scale bars = 1 cm in Figs. 5–7; 0.3 cm in Fig. 8. S =seed


Figs. 9–11. Liaoxia acutiformis Rydin, S.Q. Wu et Friis sp. nov (PB20721). 9 Overview of this reproductive 

shoot. 10 The uppermost cone in close up. No remains of seeds or male structures have been observed in this 

specimen. 11 Close up of a node. Scale bars = 1 cm in Fig. 9; 0.3 cm in Figs. 10 and 11. L =leaf;B =branch 

served. The shoot is c. 4.5 cm long and 

represents the terminal reproductive part of 

one branch (Fig. 19). The stem is erect, 

1.5 mm thick, and has distinct remnants of 

longitudinal striations. Leaves are not present 

in the preserved part of the shoot. Reproduc-


tive parts are positioned at two nodes separated 

by a short (6 mm) internode. Branching 

is opposite and with multiple axillary units. 

Cones are rounded, and vary in length between 

3.5 and 4 mm (up to 15 mm long including the 

extended bract apex), and are 2–3 mm wide. 

Four cones are positioned axillary at the 

lowermost node (Fig. 20). They are sessile to 

shortly pedunculate. Each cone comprises only 

1–2 pairs of bracts, which are reflexed and 

decussately arranged. Bracts are probably 

ovate, 10–15 mm long and 0.1–0.5 mm wide, 

and have a long pointed (setose) apex 

(Fig. 20). They have indistinct remains of two 

parallel veins (Fig. 20). The upper node comprises 

sessile cones, densely crowded into a 

head-like structure. Seeds are positioned in the 

axil of the bracts. They are poorly preserved, 

but appear elliptic, 2.5–4 mm long and c. 

1 mm wide. 

This plant differs from the other species of 

Liaoxia in the multiple numbers of sessile 

cones at nodes, superficially forming head-like 

structures. Another obvious difference is the 

extended, very long and narrow apex of the 

cone bracts, 10–15 mm long. The bracts of 

other species described here are generally only 

2–4 mm, (6–7 in L. robusta). 

Discussion 

The type species, Liaoxia chenii, was originally 

described as an angiosperm (Cyperaceae) by 

Cao et al. (1998). In the same work Cao et al. 

described another species, Eragrosites changii, 

also assigned to the monocots (Poaceae). The 

gnetalean affinity of these two species was, 

however, soon pointed out by several authors 

(Sun et al. 1998, Guo and Wu 2000). Both 

species are here assigned to Liaoxia. We have 

altered the terminology but basically followed 

the original interpretations made by Cao and 

Wu, with one exception. In the original 

description of Liaoxia it is stated that the cone 

bracts (‘‘glumes’’) are helically arranged (Cao 

et al. 1998), but according to our observations 

cone bracts are opposite and decussately 

arranged. 

Nomenclatural comments. In 2000, Liaoxia 

chenii and Eragrosites changii were re-described 

jointly as an ephedroid species, Ephedrites 

chenii (Guo and Wu 2000), based on the 

original material of Cao et al. (1998) and one 

additional specimen. This taxonomic treatment 

was followed by Sun et al. (2001), who 

based their description on the same specimens 

as well as new material. There are, however, 

problems with the approach of joining Liaoxia 

chenii and Eragrosites changii into a single 

species. The specimens originally described as 

Liaoxia chenii have a distinct ephedroid habit 

with opposite branching, long slender leaves in 

opposite and decussate arrangement at the 

nodes, and cone bracts with a distinctly 

pointed apex (referred to as an ‘‘awn’’ by 

Cao et al. 1998). Eragrosites changii (Cao et al. 

1998) also represents a plant with an ephedroid 

habit, but it differs from Liaoxia chenii in that 

leaves are absent, cones have more bracts and 

the bracts are shorter, apparently with an 

acute to obtuse apex. We find these differences 

sufficiently marked to warrant a separation of 

the specimens into two different species. 

Further, the use of the genus Ephedrites is 

inappropriate for ephedroid fossils. The genus 

was originally described by Go¨ppert and 

Berendt (1845), based on stems with female 

reproductive units preserved in Baltic amber 

from the Early Cenozoic of Europe. Additional 

material, including male structures, 

convinced Go¨ppert that these plants belonged 

to Ephedra (Go¨ppert 1853) and he transferred 

the type species (Ephedrites johnianus) to the 

extant genus (Go¨ppert 1853, Go¨ppert and 

Menge 1883). A few years later, Conwentz 

(1886) argued that the male structures probably 

represented poorly preserved material of 

Castanea whereas the female structures (the 

type) belonged to the angiosperm family 

Loranthaceae and he transferred Ephedra 

(Ephedrites) johnianus to Patzea johnianus 

(Conwentz 1886). 

In 1891, Saporta made an emended diagnosis 

of Ephedrites (citing the Go¨ppert and 

Berendt type material from 1845). He included 

two species: one new species based on seeds


Figs. 12–15. Liaoxia elongata Rydin, S.Q. Wu et Friis sp. nov. 12–13 The central part of the plant is preserved 

in this specimen (PB20723). Note the narrowly elongated cones with erect bracts, and a single, smaller and 

rounded, probably immature cone. 14–15 The uppermost part of a reproductive shoot (PB20724). Leaves are 

absent in this species. Scale bars = 1 cm in Figs. 12 and 15; 0.3 cm in Figs. 13 and 14. C =cone 

from the Jurassic of France (Ephedrites armaillensis 

Saporta), and Ephedrites antiquus, 

described by Heer (1876) based on Jurassic 

fossils from Ust-Balej, Siberia. Since then, 

several authors have used Ephedrites in the 

sense of Saporta (1891), (e.g. Wu et al. 1986, 

Guo and Wu 2000, Sun et al. 2001), (see also 

Table 1). The original description of Ephedrites 

(Go¨ppert and Berendt 1845) is, however, validly 

published and Ephedrites Saporta (1891) a 

later illegitimate homonym. A further complication 

is that the affinity to Ephedra of the 

material described by Saporta and Heer has 

been questioned (Arber and Parkin 1908, 

Krassilov and Bugdaeva 1988), even by Saporta 

himself (1891, p. 23). Krassilov and Bugdaeva 

(1988) re-described the winged seeds of 

Ephedrites antiquus Heer as parts of a possibly 

welwitschioid plant: Heerala antiqua (Heer) 

comb. nov. (Krassilov and Bugdaeva 1988). 

Thus, Ephedrites Go¨ppert et Brendt is the 

basionym of an angiosperm and should not be 

used for ephedroid fossils. Conservation of the 

homonym Ephedrites Saporta would be possible, 

but is problematic because of the uncertain 

affinity of the fossil material cited by Saporta 

(Saporta 1891, p. 23 and 26). These issues have 

also been discussed by Yang et al. (2005).


Table 1. Fossil material assigned to Ephedrites 

Reference Location Age Description Comments 

The type of Ephedrites. 

Belongs to Loranthaceae 

Reproductive branches 

preserved in amber 

Ephedrites johnianus Europe Oligocene- 

(Go¨ppert and Berendt 1845) 

Miocene 

(Conwentz 1886). 

Jurassic Detached leafless branches Branches and seeds-fruits of uncertain 

Detached seeds or fruits, affinity. The winged 

opposite with one flat side seeds re-described as 

Detached winged 

Heerala antiqua. 

seeds or fruits 

(Krassilov and Bugdaeva 1988), as 

welwitschioid seeds. 

Europe Jurassic Detached seeds or fruits, Of uncertain affinity. 

opposite with one flat side 

Yixian Formation, Early 

Reproductive branches The material belongs to 

China 

Cretaceous 

two separate species, previously 

described as Liaoxia chenii 

and Eragrosites changii 

(Cao et al. 1998). 


Reproductive shoot with Cones (spikes) with bracts at ‘‘nodes’’, 


Cretaceous three cones 

separated by ‘‘internodes’’ 

No leaves or nodes preserved Similar to the ‘‘Potamogeton-like 

spikes’’ from Manlej (Krassilov 1982). 


Vegetative shoot Strictly dichotomously branched. 



Not Gnetales, perhaps 

not a seed plant. 

Europe Oligocene-Miocene Reproductive branches Not Gnetales. Commented e.g. by 

preserved in 

Conwentz (1886) and Arber 

amber 

and Parkin (1908). 

Europe Eocene Vegetative branches; Not Ephedra. Has been 

fragmented and probably commented e.g. by Saporta (1891) 

poorly preserved. 

and Arber and Parkin (1908). 

Alternate branching 

Xiaomeigou Jurassic Reproductive branches, Fossils with affinity to Ephedra. 

Formation, China 

fragmented 

No reproductive details preserved. 

Sibiria 

(Ust-Balej) 

Ephedrites 

antiquus (Heer 1876) 

Ephedrites armaillensis 

(Saporta 1891) 

Ephedrites chenii 

(Guo and Wu 2000) 

Ephedrites? elegans 

(Sun et al. 2001) 

Ephedrites guozhongiana 

(Sun et al. 2001) 

Ephedra mengeana 

(Go¨ppert and Menge 1883) 

Ephedrites sotzkianus 

(Unger 1851) 

Ephedrites sinensis and 

E. exhibens 

(Wu et al. 1986)

252 C. Rydin et al.: Cretaceous ephedroids from China


Considering the nomenclatural problems with 

the taxon Ephedrites and the difficulty to 

unambiguously correlate the present material 

with extant Ephedra, we prefer to keep the 

name Liaoxia, and suggest that Liaoxia is used 

for Ephedra-like megafossils that cannot be 

unambiguously assigned to the extant genus. 

Interpretation of the new fossils and 

comparison with extant species. The material 

presented here comprises impression-compression 

fossils with remains of oxidized organic 

material. Most specimens have stems, leaves, 

and cones in connection, but none of the fossils 

is preserved as whole plants and none has 

roots attached. No anatomical details are 

preserved. Characters are summarised in 

Table 2. The reconstruction of Liaoxia chenii 

(Fig. 21) is based on the holotype (PB17800) 

and the new specimens (PB20717–PB20718). 

Vegetative characters of Liaoxia. The fossils 

have erect stems, which are longitudinally 

striate probably from preserved fibers. Upper 

parts are thinner than the basal parts and in all 

species the stems become wider at the nodes. 

Liaoxia robusta is larger than the other species 

and has the widest stems, but the variation is 

generally larger within each plant than 

between them. 

Leaves are absent in Liaoxia changii and L. 

elongata; leaf scars are missing in all specimens. 

In Liaoxia longibractea, only the uppermost 

part of a reproductive shoot is preserved 

and it is unknown whether or not it had leaves. 

The other species all have narrow, linear 

leaves, opposite at nodes. The leaf bases are 

probably sheeted in all the species, but the 

poor preservation prevents unambiguous conclusions. 

The venation is also generally poorly 

preserved, but obvious in at least some parts of 

the leaves. In all species there is a primary 

parallel venation and no second order venation. 

Liaoxia chenii and L. acutiformis appear 

to have two parallel veins. Liaoxia robusta has 

four veins. 

In extant Ephedra, the size and shape of 

leaves and stems may vary significantly within 

and between species (Gifford and Foster 1989) 

and the variation in the fossils is covered in the 

extant genus. For example, Ephedra leaves are 

generally minute (less than 10 mm long), ovate 

to triangular in shape, but Ephedra foliata has 

linear leaves with a well-developed lamina, 

often 10–15 mm long, sometimes extending up 

to 40 mm in length (Freitag and Maier-Stolte 

1994). Leaves of Ephedra have 2–3 parallel 

veins (Kubitzki 1990). Second order venation 

is unknown in Ephedra, but occurs in Gnetum 

and Welwitschia. 

Cones and cone bracts of Liaoxia. The 

cones of Liaoxia chenii and L. robusta are 

obovate and wide, whereas the cones of L. 

acutiformis and L. changii are elongate to 

slightly obovate. Cones of L. elongata are 

narrowly elongate, but one of the cones of L. 

elongata has a distinctly different shape and is 

smaller and rounded. It was probably preserved 

in an immature stage. In L. longibractea, 

the cones are rounded to obovate and 

several cones are densely crowded at nodes, 

forming a head-like structure. Multiple axillary 

branching resulting in four or more cones at a 

node is obvious in Liaoxia robusta, L. longibractea 

and L. elongata, and this feature is also 

common in extant Ephedra. Presence of multiple 

axillary buds is a synapomorphy for the 

Gnetales (Crane 1996, Doyle 1996). 

Liaoxia chenii has 2–6 pairs of ovate to 

triangular cone bracts with a pointed apex. 

b 

Figs. 16–20. Liaoxia robusta Rydin, S.Q. Wu et Friis sp. nov. and Liaoxia longibractea Rydin S.Q. Wu et Friis 

sp. nov. 16–18 Liaoxia robusta sp. nov (PB20719–PB20720); a large species with preserved seeds, also in the axil 

of proximal cone bracts. Leaves and stems are surrounded by precipitations that make them appear wider than 

they are. 19–20 Liaoxia longibractea sp. nov. (PB20725–PB20726); the uppermostpartofareproductiveshoot. 

It is unknown if this species had leaves or not. Note the spectacular cone bracts, and the densely crowded cones 

that form head-like structures. Scale bars = 1 cm in Figs. 16–20. S =seed;L =leaf


Table 2. Species of Liaoxia 

Unit: mm. Liaoxia Liaoxia chenii Liaoxia chenii Liaoxia chenii Liaoxia acutiformis Liaoxia 

Liaoxia elongata 

chenii PB17800 PB17801 PB20717 PB20718 PB20721 

elongata PB20724 PB20723 

Holotype Paratype New material New material New material New material New material 

Photo Fig. 1 – Figs. 3–4 Fig. 2 Figs. 9–11 Figs. 14–15 Figs. 12–13 

Branching Opposite Opposite Opposite Opposite Opposite Opposite-decussate Opposite 

Multiple axillary b. No No No No No No Yes 

Internode length 8–40 c. 12 8–17 ? 6–14 9–13 ? 

Stem width 1–3 0.5–1.5 0.5–2.0 0.5–1.5 0.3–1.4 0.4–1.0 0.5–1.5 

Leaf shape Linear Linear Linear Linear Linear Absent Absent 

Leaves length 20 5 7 5 2.7–7.0 — — 

Leaves width 1 0.1–0.3 0.1–0.3 0.3 0.2 — — 

Leaf venation 2? ? 2? 2 2? — — 

Cone shape Obovate Obovate Obovate Obovate Elongate 

Elongate Elongate 

(to narr. 

obovate) 

Cone length 5–10 4–6 4–6 5–7 3.5–6.0 5–6 (3-)6–10 

Cone width 3–4 2–3 2.5–5.0 3–4 1.7–2.7 2 3 

Cone attachment SessileSessileSessile- Pedunculate SessilePedunculateSessilepedunculatepedunculatepedunculatepedunculatesessilepedunculate 

No. of 

2–6; 

2–6; 2–6; 2–6; 6–12; 

8–10; erect 10–12; erect 

bract pairs reflexed reflexed reflexed reflexed erect-slight. 

reflexed 

Bract length 4 3–4 3–4 4 1.5–2.0 2.5–3.5 4 

Bract width 0.6 ? a 

0.3–0.8 0.5 ? a 

? a 

? a 

Bract shape Ovate (to Ovate (to Ovate (to Ovate (to Narrowly Narrowly Narrowly 

triangular) triangular) triangular) triangular) ovate 

ovate 

ovate 

Bract apex Acute to Acute to Acute to Acute to Acute Attenuate Attenuate 

attenuate attenuate attenuate attenuate 

Bract 

2 parallel ? 2 parallel 2 parallel ? ? ? 

venation 

Seed shape ? ? Ovoid-elliptic ? ? — — 

Seed length ? ? 1 ? ? — — 

Seed width ? ? 0.3–0.7 ? ? — — 

Gender Female Female Female Female Male? Male? Male?


Photo – Fig. 5 – Figs. 6–8 Figs. 16–18 Figs. 19–20 

Branching Opposite Opposite Opposite Opposite- Opposite Opposite 

decussate 

Multiple axillary b. No? No? No? No Yes Yes 

Internode lenght 8–40 8–40 10 10–18 15–40 6 

Stem width 0.5–4.0 0.5–4.0 0.3–0.8 0.7–1.7 1.5–2.0 1.5 

Leaf shape Absent absent absent absent Linear ? 

Leaves length — — — — 15–20 ? 

Leaves width — — — — 0.5–1.0 ? 

Leaf venation — — — —. 3–4 ? 

Cone shape ElongateElongateElongate- Obovate Obovate 

Rounded 

obovateobovateobovate to elongate to elongate 

Cone length 5–6 5–6 4–5 5–6 7–16 3.5–4 ()15 

including 

bract apex) 

Cone width 2.5–3.0 2.5–3.0 1.5–2.0 2.5–3.0 6–8 2–3 

Cone attachment SessileSessileSessileSessileSessile- Sessile- shortly 

pedunculatepedunculatepedunculatepedunculatepedunculate pedunculate 

Bract pairs; 

6–10; erect- 6–10; erect- c. 8; erect- 6–10; erect- 4–10; reflexed 1–2; reflexed 

position 

slightlyslightlyslightlyslightly reflexed reflexed reflexed 

reflexed 

Bract length 2 2 2 2 4–7 10–15 

Bract width 0.3 0.3 0.3 ? a 

? a 

0.1–0.5 apically 

Bract shape Ovate Ovate Ovate Ovate Ovate Ovate? 

Bract apex Acute to Acute to Acute to Acute to Acute to 

Setose 

obtuse 

obtuse 

attenuate obtuse 

attenuate 

Bract venation ? ? ? ? 1–2 parallel? 2 parallel 

Seed shape — — ? Ovoid Rounded-elliptic Elliptic 

Seed length — — 1 0.8–1.0 2.5–3.5 2.5–4.0 

Seed width — — 0.2–0.3 0.2–0.3 1.2–2.0 c. 1.0 

Gender Mix? Mix? Female (mix?) Female Female Female 

Notes. All units in mm. —: Feature absent. ?: Feature poorly preserved. a : Bracts folded and overlapping; exact width not possible to say.


Fig. 21. Reconstruction of Liaoxia chenii, Cao et 

S.Q. Wu (emerd. Rydin, S.Q. Wu et Friis) based on 

the holotype (PB17800) and the new specimens 

(PB20717–PB20718). Drawing by Pollyanna von 

Knorring. Scale bar = 1 cm 

The cones of L. acutiformis and L. changii 

contain more bracts (6–12 in the former, 6–10 

in the latter), but each bract is smaller and has 

a less distinctly pointed, acute apex. In L. 

elongata the cones have c. 10 pairs of pointed, 

narrowly ovate bracts. Several cones of Liaoxia 

robusta have approximately 4 pairs of 

cone bracts but there are also larger cones with 

up to 10 bract pairs. The cones of L. longibractea 

consist of only 1–2 pairs of bracts, 

which are very long and conspicuous with their 

extended, narrow apex. They are unique 

among ephedroid plants, we have not seen 

anything similar in any living or fossil species. 

The cones of extant Ephedra are compound, 

consisting of cone bracts and seeds 

with extra-integumentary structures of bract 

(leaf) origin (Pearson 1929, Crane 1985, Takaso 

1985, Pedersen et al. 1989, Yang 2001, 

2004). Our interpretation is that the cones of 

Liaoxia are also compound with the same 

structural arrangement as those of Ephedra, 

but the preservation of the material prevents 

unambiguous conclusions. Ephedra cones are 

generally composed of 2–8 pairs of bracts, 

sometimes more. This is in agreement with the 

condition in the fossil species, even though the 

large specimen of L. elongata has more bracts 

than usually seen in extant Ephedra. Many 

extant species have obovate to rounded cone 

bracts with an obtuse or rounded apex, but 

ovate bracts with a pointed apex also occur in 

some species. 

Seeds. Seeds are preserved as compressions 

or impressions in several of the fossils, even 

though no anatomical details are preserved. 

Like extant Ephedra, Liaoxia chenii has seeds 

only in the axil of distal bract. The cone bracts 

are delicate and were probably membranous, 

not fleshy. They are often fully reflexed, and 

several cones seem to lack seeds, indicating 

wind dispersal and preservation at a late stage 

in the reproduction phase. Delicate cone bracts 

with two veins that become reflexed at seed 

maturity can for instance be seen in the 

African species Ephedra alata. 

Contrary to the cones of Liaoxia chenii and 

extant Ephedra, the cones of L. changii, L. 

robusta and L. longibractea appear to have a 

seed in the axil of most bracts, also in proximal 

part of the cones. This is interesting as it differs 

significantly from Ephedra, which has seeds 

mainly in a distal position, but is more similar 

to Welwitschia where seeds also occur proximally 

in the cone. This is conceivably an 

ancestral state present in some of the Cretaceous 

fossils and retained in Welwitschia, (but 

see also the discussion below on the distinction 

between ephedroid and welwitschioid fossils). 

In Liaoxia chenii and L. changii, the seeds 

are ovoid to elliptic and small. In Liaoxia 

robusta, and L. longibractea they are rounded


to elliptic and larger, but all the fossil seeds are 

much smaller than seeds of extant Gnetales. 

Seeds of Ephedra are at least 6–7 mm long 

whereas the fossils are only 1–4 mm. The small 

size of the fossil seeds is, however, in accordance 

with other ephedroid seeds from the 

Early Cretaceous described from Portugal and 

North America (Rydin et al. 2004, Rydin et al. 

2006). 

Gender. Most species of Ephedra are dioecious 

with male and female reproductive parts 

on separate plants. Male cones often comprise 

more bracts than female cones of the same 

species and the shape of male and female cone 

bracts may differ within a species. All Liaoxia 

specimens currently known have only one kind 

of cones and we therefore assume that these 

ephedroid fossils were also dioecious. Liaoxia 

chenii, L. changii, L. robusta and L. longibractea 

are clearly female plants. Their cone bracts 

are reflexed and seeds are present in the axil of 

bracts. In contrast, Liaoxia acutiformis and L. 

elongata have bracts that are more erect and 

without remains of seeds or microsporangiophores. 

The poor preservation makes interpretation 

of reproductive details difficult, but the 

absences of seeds and the erect position of the 

cone bracts might suggest that L. acutiformis 

and L. elongata represent male plants. Male 

organs of extant Ephedra generally detach 

easily, shortly after pollination, which may 

explain the absence of preserved microsporangia 

in these putatively male plants. 

Because the Early Cretaceous ephedroids 

are interpreted as dioecious, it is possible that 

the putatively male specimens actually belong 

to the same species as one or two of the female 

specimen. To explicitly correlate female and 

male plants would require epidermal or other 

cellular details not present in this material. It 

is, however, interesting to note that Liaoxia 

acutiformis is vegetatively closely similar to L. 

chenii, but differs in the number and shape of 

the cone bracts. Liaoxia acutiformis may be 

very closely related to L. chenii, speculatively, 

the male plant of L. chenii. Similarly, Liaoxia 

changii and L. elongata are vegetatively similar, 

both lacking leaves, but differ in shape of 

cones and cone bracts. Both species have been 

found in the Fanzhangzi Section in Lingyuan 

and, again speculatively, Liaoxia elongata 

could be the male plant of Liaoxia changii. 

Other gnetalean fossils from eastern 

Asia. Several ephedroid fossils, other than 

those described here, have been reported from 

China and else where (Table 3). Among them 

are Ephedrites sinensis and Ephedrites exhibens 

(Wu et al. 1986) from the Jurassic Xiaomeigou 

Formation of Qinghai. The fossils are fragmentarily 

preserved and difficult to compare 

with the present material, but they seem to 

differ from Liaoxia species in having only a 

single pair of seeds and bracts. 

Alloephedra xingxuei (Tao and Yang 2003) 

from the Dalazi Formation, China, is an 

Early Cretaceous fossil interpreted as a close 

relative of Ephedra. However, the nature of 

branching and reproductive structures is not 

fully clear from descriptions and illustrations 

and there are features that are not compatible 

with the Gnetales (e.g. possibly alternate 

branching). 

Ephedra archaeorhytidosperma (Yang et al. 

2005), collected from the Jianshangou Bed that 

also contains Liaoxia chenii and L. robusta, is 

clearly ephedroid with striate stems, opposite 

branching, terminal female cones consisting of 

1–2 seeds with extended micropylar tubes and 

bracts or bract scars. Ephedra archaeorhytidosperma 

differs from most of the Liaoxia species 

presented here in that each cone consists of 

only 1–2 seeds and bract pairs, whereas the 

Liaoxia fossils have cones with more bracts. 

Liaoxia longibractea has cones with few bracts 

but the very long and narrowly extended cone 

bracts of L. longibractea are very different 

from those of Ephedra archaeorhytidosperma. 

The material of Ephedra archaeorhytidosperma 

comprises one associated triangular leaf, which 

is poorly preserved and not clearly attached to 

the specimen. There is no evidence of leaves at 

the nodes. Thus Ephedra archaeorhytidosperma 

may lack leaves, as do some species of Liaoxia. 

Sun et al. (2001) described two new species 

of ephedroid fossils from the Yixian Formation 

of Liaoning. Branching in Ephedrites


Table 3. Fossils with affinity to Ephedra 

Reference Location Age Description Comments 

Plant with an ephedroid habit, 

but is interpreted as having 

alternate branching, which is 

otherwise unknown in the 

Reproductive 

shoot 

Dalazi Formation, China Early 


Alloephedra xingxuei 

(Tao and Yang 2003) 

Gnetales. 

Reproductive Ephedroid plant similar to 

shoot 

Liaoxia, but appears to have 

longer or distinctly pointed 

cone bracts. 

Reproductive Well-preserved Ephedra-fossil, 

shoot 

with vegetative and reproductive 

parts in connection. The large 

‘‘mature’’ cone is detached and 

could potentially belong to another 

species. 

Coalified seeds Well-preserved Ephedra seeds 

with anatomical details and in 

situ pollen. 

Coalified seeds Well-preserved Ephedra seeds 


situ pollen. 

Coalified seeds Well-preserved ephedroid seeds 


situ pollen. 

Reproductive The material belongs to two se- 

shoots 

parate species, previously described 

as Liaoxia chenii and 

Eragrosites changii (Cao et al. 

1998). 

Reproductive Similar to the ‘‘potamogeton-like 

shoot 

spikes’’ from Manlej (Krassilov 

1982). No leaves or nodes preserved. 

Cone (spike) with bracts 

at ‘‘nodes’’, separated by 

‘‘internodes’’. 

Manlaj, Mongolia Early 


‘‘Cyperacites sp.’’ plate 20, 

figs. 240–243 

(Krassilov 1982) 

Yixian Formation, China Early 


Ephedra archaeorhytidosperma 

(Yang et al. 2005) 

Early 


Potomac Group, North 

America 

Ephedra drewriensis 

(Rydin et al. 2006) 

Buarcos, Portugal Early 


Ephedra portugallica 


Buarcos, Portugal Early 


Ephedrispermum lucitanicum 


Yixian Formation, China Early 


Ephedrites chenii (Guo and Wu 2000). 

(Synonym of Liaoxia chenii 

Cao et al., 1998) 

Ephedrites? elegans (Sun et al. 2001) Yixian Formation, China Early 

Cretaceous


Plants with affinity to Ephedra, 

no reproductive details pre- 

Reproductive 

shoot fragments 

Xiaomeigou Formation, China Early 

Jurassic 

Ephedrites sinensis and E. exhibens 

(Wu et al. 1986) 

served. 

Plant with affinity to Ephedra, 

initially described as an angiosperm. 

Leaves absent. 

Initially thought to be an angiosperm, 

later described as Phyllotheca 

wonthaggiensis 

(Sphenopsida) (Drinnan and 

Chambers 1986). Suggested to 

be ephedroid by Krassilov et al 

(1998). 

Very similar to extant Ephedra, 

but no anatomical details or in 

situ pollen. Initially described as 

an angiosperm. 

Cones (spikes) with bracts at 

‘‘nodes’’, separated by ‘‘internodes’’, 

similar to Ephedrites? 

elegans. 

The material indicates that 

ephedroid plants were present in 

north-western Gondwana. 

Reproductive 

shoot 

Eragrosites changii (Cao et al. 1998) Yixian Formation, China Early 


Vegetative 

shoot fragments 

Koonwarra Bed, Australia Early 


Leongathia elegans 

(Krassilov et al. 1998) 

Reproductive 

shoot 

Liaoxia chenii (Cao et al. 1998) Yixian Formation, China Early 


Reproductive 

‘‘spike’’ 

Manlaj, Mongolia Early 


‘‘Potamogeton-like spike’’ 

(Krassilov 1982) 

Reproductive 

shoots 

Early 


Crato Formation, 

South America 

Undescribed fossils (see e.g. 

Mohr et al. 2004)


guozhongiana Sun et Zheng (Sun et al. 2001) 

appears to be strictly dichotomous and, as a 

consequence of the absence of overtopping, all 

branches are of about equal length. Such a 

branching pattern is unknown for the Gnetales 

and other seed plants, and the affinity of 

Ephedrites guozhongiana to Gnetales uncertain. 

Ephedrites? elegans Sun et Zheng (Sun et 

al. 2001) was based on a reproductive branch 

from the Yixian Formation. Sun et al. (2001) 

included in this species a fossil previously 

described as ‘‘Potamogeton-like spike’’ from 

the Early Cretaceous of Mongolia (Krassilov 

1982). The Chinese fossil has two lateral and 

one terminal reproductive axes subtended by a 

pair of linear leaves. Reproductive axes comprise 

c. 5 pairs of broadly ovate leaves or 

bracts with a pointed apex and 2–3 distinct 

veins. They are similar to the cones of Liaoxia, 

but differ in having distinct internodes between 

the bract pairs. The ‘‘Potamogeton-like spike’’ 

from Mongolia consists of a single spike with 

five nodes separated by prominent internodes. 

At each node there are 2–3 ‘‘nutlets’’ apparently 

subtended by bracts with a pointed apex. 

Ephedrites? elegans and the ‘‘Potamogeton-like 

spike’’ from Mongolia show some resemblance 

to Ephedra and welwitschioid fossils in the 

striate stems and linear leaves present at least 

in the Chinese fossil. However, spikes with 

distinct and clearly definable internodes and 

reproductive structures at nodes are characteristic 

for extant Gnetum, and are not seen in 

Ephedra and Welwitschia. 

Yabe and Endo (1935) described fossils 

from Lingyuan as possible members of the 

extant angiosperm genus Potamogeton. Later 

these fossils were transferred to Ranunculus 

(Miki 1964), but Guo and Wu (2000) suggest 

that they are related to Ephedra, and Sun et al. 

(2001) included them in Ephedrites chenii 

(Liaoxia chenii). The published figures (Yabe 

and Endo 1935, Figs. 1–3) indicate a vegetative 

morphology similar to that of Liaoxia, but 

show differences in reproductive structures. 

Unfortunately, however, there are no details of 

the fossils that could be used for comparative 

studies. 

A possible member of Liaoxia is ‘‘Cyperacites 

sp.’’ from Mongolia (Krassilov 1982), 

characterised by having ‘‘a terminal cyme of 

three spike-like structures’’ and ‘‘at the base of 

the cyme three hair-like appendages’’. Like 

Liaoxia chenii it was originally interpreted as 

member of the angiosperm family Cyperaceae, 

but it is most likely a gnetalean plant. The 

‘‘cymes’’ are similar to cones of Liaoxia, and 

apparently composed of acuminate bracts. The 

‘‘hair-like’’ structures at the base of the cyme 

are probably the veins of two opposite leaves, 

one preserved vein of the right leaf, and two 

preserved veins of the left leaf. 

Phylogenetic implications. The vegetative 

characters of the fossils presented here (opposite 

and decussate phyllotaxis, linear leaves 

positioned at distinct nodes separated by long 

internodes, parallel venation), in combination 

with the reproductive characters (seeds in the 

axil of cone bracts in decussate arrangement) 

exclude a relationship to any other group than 

the Gnetales. Within the Gnetales, Liaoxia are 

similar to Ephedra in gross morphology, but 

several of these characters (elongated leaves 

with parallel venation, cones consisting of 

oppositely arranged cone bracts with axillary 

seeds) are not unique to Ephedra, but occur 

also in Welwitschia. The presence of seeds 

inside most cone bracts in the cones of Liaoxia 

robusta and Liaoxia changii, would even 

suggest a closer affinity to Welwitschia. 

Considering only extant species, it may 

seem easy to distinguish between Ephedra and 

Welwitschia, but among Cretaceous plants, 

this distinction is not always straightforward. 

For example, Gurvanella first described from 

the Early Cretaceous of Mongolia (Krassilov 

1982) and later also reported from the Yixian 

Formation in Liaoning (as Chaoyangia Duan, 

1998), has an ‘‘ephedroid’’ vegetative habit 

with opposite branching, striate stems and 

linear leaves with parallel venation. However, 

the seeds are surrounded by a distinct wing, in 

gross morphology similar to the seed wing of 

Welwitschia. The venation of the Gurvanellawing 

has dichotomies and anastomoses, which 

is unknown in Ephedra, but present in leaves


and cone bracts of Welwitschia (Rodin 1953, 

1958). 

Yang et al. (2005) argued that Chaoyangia 

shares most of its characters with Ephedra, and 

Zhou et al. (2003) maintained that the combination 

of ephedroid and welwitschioid characters 

in Gurvanella (Chaoyangia) supports a 

closer relationship between Ephedra and Welwitschia 

than currently suggested based on 

molecular data (see for example studies by 

Magalloń and Sanderson 2002, Rydin et al. 

2002, Burleigh and Mathews 2004). However, 

the similarities between Ephedra and Welwitschia 

are non-informative plesiomorphic features, 

and the same is probably true for the 

similarities between Ephedra and Gurvanella 

(Chaoyangia). Like Drewria potomacensis 

Crane et Upchurch (Crane and Upchurch 

1987), Welwitschiostrobus murili (Dilcher et 

al. 2005) and several undescribed Crato plants 

(Barbara Mohr personal communication), 

Gurvanella (Chaoyangia) possesses uniquely 

derived characters of Welwitschia, but has also 

retained primitive vegetative habits with opposite 

branching and phyllotaxis, swollen nodes 

and linear leaves with parallel venation, closely 

resembling that of Ephedra. These characters 

are general features of the Gnetales; several of 

them are in fact also present in Gnetum. It has 

for example been shown that the ‘‘reticulate’’ 

venation pattern in Gnetum actually develops 

from parallel venation, and is a result of 

successive dichotomies in 5–10 parallel veins 

located in the centre of the leaf (Rodin 1967). 

Apart from molecular data, there are 

several morphological synapomorphies that 

support the Gnetum-Welwitschia clade (second 

order venation, paracytic stomata, astrosclerids, 

embryo feeder etc, see e.g. Crane 1985, 

Doyle 1996), and the sister relationship between 

Gnetum and Welwitschia is thus well 

corroborated. The fossils of Liaoxia do not 

possess any of the features characterizing this 

clade and we therefore exclude a close relationship 

to Welwitschia (and the Gnetum- 

Welwitschia crown group as a whole). 

We hypothesize that the species of Liaoxia 

are most closely related to Ephedra among 

extant plants, perhaps even nested within 

Ephedra, but unambiguous support for this 

suggestion is not available. Synapomorphies 

for Ephedra mainly constitute structural details 

of the seed envelope and pollen grains, not 

preserved in this type of material. Therefore, it 

cannot be fully ruled out that the Liaoxia 

fossils could represent ephedran or gnetalean 

stem lineage(s). Resolving higher level relationships 

among species of Liaoxia, Ephedra 

and ephedroid fossils in the literature is a 

challenging task for the future. 

Conclusions 

The Ephedra-like fossils discussed in this paper 

have been assigned to the genus Liaoxia, 

previously established by Cao et al. (1998). 

New material of six species, of which four are 

new, is presented. The features of the fossils 

exclude a relationship to any other group than 

the Gnetales. Within the Gnetales, a relationship 

to the Gnetum-Welwitschia clade can be 

excluded, however, the preservation stage of 

the fossils prevents an unambiguous association 

with extant Ephedra. Because the name 

Ephedrites, previously used for ephedroid 

fossils, is the basionym of an angiosperm and 

unsuitable for gnetalean fossils, we have used 

the genus name Liaoxia and suggest that 

Liaoxia is used in the future for Ephedra-like 

megafossils that cannot be unambiguously 

assigned to the extant genus. 

The species of Liaoxia are similar in overall 

gross morphology, but differ from each other 

and from previously described ephedroid fossils 

in morphological details such as the absence or 

presence of leaves, shape of the cones and in 

shape and position of the cone bracts. 

Several studies have indicated that the 

diversity of the Gnetales was larger in 

the Early Cretaceous than it is today and the 

fossils presented here further document this. 

The crown group Gnetales is represented in the 

Early Cretaceous by Cratonia (Rydin et al. 

2003), Welwitschiostrobus (Dilcher et al. 2005), 

coalified Ephedra seeds (Rydin et al. 2004, 

Rydin et al. 2006) and probably also by


Drewria (Crane and Upchurch 1987), Gurvanella 

(Chaoyangia) (Krassilov 1982, Duan 

1998) and undescribed fossils from Brazil 

(Barbara Mohr, unpubl. data) and China 

(Rydin et al., unpubl. data). 

Whether the ephedroid fossils presented 

here belong to crown group Gnetales or to 

extinct stem groups, is yet to be discovered. We 

consider them members of the ephedran lineage, 

but due to restricted information in the fossils 

and poorly understood morphological diversity 

of extant Ephedra, it is not possible to assign 

them to any particular subgroup of Ephedra or 

to clearly exclude them from the extant genus. 

The authors thank Susana Magalloń and an 

anonymous reviewer for valuable comments on the 

text, Chen Peiji for information on the geology of 

the Yixian Formation, Arne Anderberg for nomenclatural 

comments and suggestions and Yvonne 

Arremo for assistance with photography. The 

project was supported by grants from the Swedish 

Research Council (EMF), The Asian-Swedish 

Research Link Programme (EMF and Zhou Zhonghe), 

NSFC (SQW) and from the Royal Swedish 

Academy of Sciences (CR). 

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Addresses of the authors: Catarina Rydin, 

(e-mail: catarina.rydin@nrm.se) and E. M. Friis, 

Swedish Museum of Natural History, Department 

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Sweden. S. Q. Wu, Nanjing Institute of Geology 

and Palaeontology, Chinese Academy of Sciences, 

Nanjing, 210008, China.

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