FOC_25_Epidendroidea..

466
EPIDENDROIDEAE
with a raised, central ridge or callus; column short, stout; stipe short, broad; viscidium broadly ovate; pollinia 4, appearing as 2
unequal masses, waxy.
About 13 species: from NE India and mainland Asia to Indonesia, New Guinea, and the Pacific islands; one species in China.
1. Arachnis labrosa (Lindley & Paxton) H. G. Reichenbach,
Bot. Centralbl. 28: 343. 1886.
窄唇蜘蛛兰 zhai chun zhi zhu lan
Stems to 50 cm, 7–10 mm in diam., rigid, with many
nodes and leaves. Leaves distichous; leaf blade lorate or linear,
15–30 × 1.6–2.2 cm, leathery, obtusely unequally bilobed. Inflorescence
arising from within leaf sheath, ascending, racemose,
to 1 m, occasionally branched, laxly many flowered;
floral bracts reddish brown, broadly ovate, 5–8 mm, obtuse.
Flowers pale yellow with reddish brown spots or markings
mostly along margins and at apex, or greenish yellow without
red-brown markings; pedicel and ovary brown, ca. 2 cm, slender.
Sepals oblanceolate, ca. 18 × 3 mm, obtuse. Petals oblong,
9–11 × 2–5 mm, subacute; lip ca. 1 cm, fleshy, 3-lobed; lateral
lobes erect, subtriangular, small, ca. 2 mm wide at base, obtuse;
mid-lobe ligulate, fleshy, acute or obtuse, with a thickened
appendage abaxially near apex, base with 2 retrorse calli on
both sides, spurred; spur saccate-conic, 4–5 mm, thickly fleshy,
its entrance ± covered by calli. Column ca. 6 × 4 mm, stout,
base with an inconspicuous foot; rostellum triangular, apex
widely emarginate; stipe subovate-triangular, ca. 1 mm; viscidium
nearly suborbicular. Fl. Aug–Sep. 2n = 38.
Epiphytic on tree trunks at forest margins, lithophytic on rocks in
valleys; 600–1200 m. Guangxi, Hainan, C and S Taiwan, S Yunnan
[Bhutan, NE India, ?Japan (Ryukyu Islands), Myanmar, S Vietnam].
1a. Flowers pale yellow with reddish brown
spots or markings mostly along margins
and at apex; petals ca. 2 mm wide ............. 1a. var. labrosa
1b. Flowers greenish yellow, without red-brown
markings; petals 4–5 mm wide ..................... 1b. var. zhaoi
1a. Arachnis labrosa var. labrosa
窄唇蜘蛛兰(原变种) zhai chun zhi zhu lan (yuan bian zhong)
Arhynchium labrosum Lindley & Paxton, Paxt. Fl. Gard.
1: 142. 1850; Arachnanthe bilinguis (H. G. Reichenbach) Bentham;
Armodorum labrosum (Lindley & Paxton) Schlechter;
Renanthera bilinguis H. G. Reichenbach; R. labrosa (Lindley &
Paxton) H. G. Reichenbach.
Flowers pale yellow with reddish brown spots or markings
mostly along margins and at apex. Petals ca. 2 mm wide.
Epiphytic on tree trunks at forest margins, lithophytic on rocks
in valleys; 800–1200 m. Guangxi, Hainan, C and S Taiwan, S Yunnan
[Bhutan, NE India, ?Japan (Ryukyu Islands), Myanmar, S Vietnam].
1b. Arachnis labrosa var. zhaoi (Z. J. Liu, S. C. Chen & S. P.
Lei) S. C. Chen & J. J. Wood, comb. et stat. nov.
赵氏蜘蛛兰 zhao shi zhi zhu lan
Basionym: Arachnis zhaoi Z. J. Liu, S. C. Chen & S. P.
Lei, Acta Bot. Yunnan. 30: 529. 2008.
Flowers greenish yellow, without red-brown markings.
Petals 4–5 mm wide.
● Epiphytic on trees; ca. 600 m. Hainan (Changjiang).
168. THRIXSPERMUM Loureiro, Fl. Cochinch. 2: 516, 519. 1790.
白点兰属 bai dian lan shu
Chen Xinqi (陈心启 Chen Sing-chi); Jeffrey J. Wood
Herbs, epiphytic, lithophytic, or rarely terrestrial, monopodial, medium-sized. Stems ascending, climbing, or pendulous, either
short with several closely spaced leaves, or long with many, well-spaced leaves. Leaves flat, never terete or laterally compressed,
sometimes fleshy, base sheathing, jointed. Inflorescence lateral, axillary, racemose, long or short, few to many flowered, a few flowers
opening at a time, flowering of many lowland species initiated by a sudden afternoon rainstorm; floral bracts either distichous and
persistent on a flattened rachis or facing all directions on terete rachis. Flowers usually ephemeral, often fully open for only half a
day, small to medium-sized, very variable, from a few millimeters to several centimeters in diam. Sepals and petals subsimilar; lip
adnate at base to end of column foot, immovable, saccate but not truly spurred, usually with a partly hairy or papillose front wall
callus, 3-lobed; lateral lobes erect; mid-lobe rather thick and fleshy. Column short, stout, sometimes winged, with a long foot; pollinia
waxy, 4, appearing as 2 unequal masses, subglobose, attached by a common short and broad stipe to a solitary viscidium. Capsule
long, slender.
About 100 species: Sri Lanka and the Himalayan region east to the Pacific islands, with an apparent center of distribution in Sumatra; 14 species
(two endemic) in China.
1a. Floral bracts distichous on a ± flattened rachis.
2a. Floral bracts ca. 5 mm apart from each other; rachis slender, shorter than 5 cm .............................................. 12. T. japonicum
2b. Floral bracts close, 1–3 mm apart from each other; rachis stout, longer than 5 cm.
3a. Leaves ovate-lanceolate, base cordate, 2–2.5(–5) cm ............................................................................. 13. T. amplexicaule
3b. Leaves oblong, base narrowed, 6–24 cm ....................................................................................................... 14. T. centipeda
1b. Floral bracts facing all directions (quaquaversal) on a terete rachis.