Highlights of the Didymellaceae - Studies in Mycology

Basionym: Sphaeronaema multirostratum P.N. Mathur, S.K. Menon
& Thirum., Sydowia 13: 146. 1959. (as "Sphaeronema").
Specimens examined: India, Maharashtra, Poona, Talegaon, from poultry farm soil,
Mar. 1959, M.J. Thirumalachar, isotype CBS H-7616, culture CBS 274.60 = IMI
081598; Maharashtra, Poona, Talegaon, from soil, Mar. 1959, M.J. Thirumalachar,
CBS H-16499, culture CBS 368.65 = PD 92/1757. The Netherlands, Hoorn,
greenhouse, from the stem of Cucumis sativus, Aug. 1967, G.H. Boerema, CBS
H-16502, culture CBS 110.79 = PD 65/8875. Unknown origin, from Cucumis sativus,
1983, PD 83/48.
Phoma pereupyrena Gruyter, Noordel. & Boerema,
Persoonia 15(3): 390. 1993.
Specimen examined: India, from a leaf of Coffea arabica, 1976, CBS 267.92 = PD
76/1014.
Group P:
This well-supported clade (BPP = 1.00, RBS = 97 %) comprises
Ph. dictamnicola and Ph. sylvatica, which are both associated with
the section Sclerophomella (Boerema et al. 1998). In addition, both
varieties of Ph. poolensis are recovered here. As in the Sclerophomella
species, an ostiole is commonly absent in Ph. poolensis var. poolensis,
a character which supports the sequence data found in the present
study. In contrast, the second variety of this species, Ph. poolensis
var. verbascicola, always produces ostiolate pycnidia (De Gruyter et
al. 1993). Both Ph. poolensis varieties can further be differentiated
on the basis of the β-tubulin sequence, and are morphologically
distinguishable in the colour of the conidial matrix. The conidia of the
type variety are on average somewhat smaller, measuring ca. 3.5–5
× 1.5–2 μm, than those of var. verbasicola, which measure 3.5–5.5
× 1.5–2.5 μm. Both varieties are known from plant hosts belonging to
the Scophulariaceae, but whereas var. poolensis is recorded as causal
agent of leaf spots and basal stem rot in snapdragon (Antirrhinum
majus), var. verbascicola is only known as saprobe of Verbascum
spp., although inoculation trials indicated that it may also have a role
as pathogen (Boerema et al. 2004). Given all these differences, it is
considered to be justified to erect a separate species for Ph. poolensis
var. verbascicola as Ph. novae-verbascicola.
Although none of the species in this group has been confirmed
to have a teleomorph (Boerema et al. 1998), it has been suggested
that Didymella winteriana is the teleomorph of Phoma sylvatica (Munk
1957). Given the topology of the tree, this association with a Didymella
species is plausible, although a sexual structure was not observed in
the present study, nor in the previous studies of Boerema & De Gruyter
(1998).
Phoma dictamnicola Boerema, Gruyter & Noordel.,
Persoonia 15(1): 90. 1992.
Specimen examined: The Netherlands, Arnhem, from a stem of Dictamnus albus,
1974, J. de Gruyter, CBS 507.91 = PD 74/148.
Phoma novae-verbascicola Aveskamp, Gruyter & Verkley,
nom. nov. pro Phyllosticta verbascicola Ellis & Kellerm.
MycoBank MB515640.
Basionym: Phyllosticta verbascicola Ellis & Kellerm., Bull. Torrey
Bot. Club 11: 115. 1884.
≡ Phoma poolensis var. verbascicola (Ellis & Kellerm.) Aa & Boerema,
in De Gruyter, Noordeloos & Boerema, Persoonia 15(3): 385. 1993. Not
Phoma verbascicola (Schwein.) Cooke, in Ravenel. 1878.
Etymology: The epithet refers to the host plant, Verbascum spp.
For a full description see De Gruyter et al. (1993).
www.studiesinmycology.org
Phoma And relAted pleoSporAleAn generA
Specimens examined: The Netherlands, Zeist, Abburg nursery, holotype L
9893.00.134; Haarlem, from dead stem material of Verbascum densiflorum, 1992,
J. de Gruyter, CBS 127.93 = PD 92/347; from stem of Verbascum sp., 1974, G.H.
Boerema, CBS 114.93 = PD 74/228.
Notes: This species is distinguishable from Ph. poolensis by to the
presence of 1–2(–5) ostioles, the colourless to whitish matrix and
the smaller conidia. On MEA, the aerial mycelium is more compact
or woolly than that of Ph. poolensis.
The variety epithet could not be elevated to species level, as
Phoma verbascicola is already occupied. This basionym, however,
probably refers to immature pseudothecia of a Pleospora species
(Boerema et al. 1996). Therefore, a new name is proposed here for
the present species.
Phoma poolensis Taubenh., Dis. Greenhouse Crops 203.
1919.
Specimens examined: Denmark, from a stem of Antirrhinum majus, July 1938,
P. Neergaard, CBS 253.38. The Netherlands, Wageningen, from a stem of
Scrophularia nodosa, 1974, G.H. Boerema, CBS 115.93 = PD 74/206; Bennekom,
from a stem of Antirrhinum majus, 1973, G.H. Boerema, CBS 116.93= PD 71/884.
Unknown origin and substrate, 1920, E.M. Smiley, CBS 113.20 = PD 92/774.
Phoma sylvatica Sacc. Michelia 2(2): 337. 1881.
Specimens examined: The Netherlands, Wageningen, from Melampyrum
pratense, 1983, J. de Gruyter, CBS 135.93 = PD 83/87; Wageningen, from a stem of
Melampyrum pratense, 1993, J. de Gruyter, CBS 874.97 = PD 93/764.
Group Q:
The Phoma species embedded in this group, Ph. commelinicicola
and Ph. eupatorii are morphologically distinct, hence their
accommodation in the sections Phoma and Macrospora
respectively. The accommodation of Chaetasbolisia erysiphoides
in this clade, the type of its genus, is unexpected. Attempted
morphological studies revealed that this strain was sterile, and
therefore recombination of the species could not be supported by
morphological data. The descriptions provided in literature (Sutton
1980, Patel et al. 1997, Reynolds 1999) suggest, however, that
this genus could very well represent a group of setose Phoma
species, although this cannot be resolved due to a lack of isolates.
The presence of setae is not recorded in other species in group
Q, and moreover, is within the Didymellaceae only known from
Peyronellaea gardeniae (Group K), and from pycnidia in some
older cultures from Epicoccum sorghi (Group M), Peyronellaea
glomerata (Group K) and Phoma herbarum (Boerema et al. 2004).
The topology and the clustering of these species cannot be further
explained by the morphology or ecology, nor by their geographical
distribution.
Phoma commelinicola (E. Young) Gruyter, Persoonia 18(1):
93. 2002.
Basionym: Phyllosticta commelinicola E. Young, Mycologia 7: 144.
1915.
Specimen examined: New Zealand, South Auckland, Alfriston, from Tradescantia
sp., 1997, K. Ramsay, CBS 100409.
Phoma eupatorii Died., Ann. Mycol. 10(5): 447. 1912.
Specimen examined: The Netherlands, Arnhem, from Eupatorium cannabinum,
1977, G.H. Boerema, CBS 123.93 = PD 77/1148.
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