Trichosma Lindley.

Herbs, epiphytic, lithophytic, or rarely terrestrial. Rhizome creeping. Stems pseudobulbous, of 1 distinctly enlarged internode, ovoid, faintly to distinctly angular in transverse section, with 2-4 leaves toward apex; base of pseudobulbs loosely covered by leaf sheaths. Leaves convolute in bud, elliptic to narrowly elliptic, leathery, articulate, tapering at base. Inflorescence axillary, erect, many flowered, pubescent; peduncle subtended by 2 or 3 imbricate sterile bracts arising from opposite leaf base; inflorescence axis covered by brown stellate hairs; floral bracts brown, narrowly ovate to triangular. Flowers opening widely, usually cream-colored to pale yellow and in some species with purple veins or purple markings on column, column foot, and lip, stellate or otherwise, large; ovary angular in cross section, sometimes winged. Sepals narrowly triangular with hairs abaxially; lateral sepals slightly ventrally broadened at base, recurved at apex; mentum distinct. Petals similar to sepals; lip simple or 3-lobed, callus absent or adorned with ridges. Column short, foot incurved; anther cap fleshy, with an obtuse apical median ridge, apex obtuse and covering erect, truncate rostellum; pollinia 8, in 2 groups of 4, each group contained within a distinct 4-chambered pouch at base of anther cap, each pollinium laterally compressed, ± deltoid in lateral view, equal in size, at base attached with white granular caudicles.

Lindley established Eria based on E. stellata (now E. javanica). The generic name is derived from the Greek έριον (erion, wool) and refers to the woolly hairs on the inflorescence and flowers. Lindley, in giving the name, was referring to Eria pubescens, now referred to Dendrolirium lasiopetalum (see p. 351). Densely woolly pubescence is indeed characteristic of Dendrolirium but not very evident in Eria s.s. In the same year, Blume (Bijdr. 340, 342, 343, 352. 1825) established the genera Callostylis, Ceratium, Dendrolirium, Mycaranthes, and Trichotosia. Lindley (Gen. Sp. Orchid. Pl. 65-70. 1830) included Blume’s Dendrolirium and his own Pinalia in Eria, including 25 species in the genus. Seidenfaden, in his treatment of Thai Eria (Opera Bot. 62: 1-157. 1982), commented, "this genus as circumscribed by Lindley and as understood by later authors, has had so many heterogeneous elements included that considerations must be given to possible separations into more genera."

Eria s.l. comprises ca. 370 species, with ca. 44 species recorded from China. Although no serious modern studies of Eria s.l. at the interspecific level have been undertaken over its entire range (apart from Seidenfaden, loc. cit.), conspecificity may be expected to be high, thereby reducing the number of described taxa.

Pridgeon et al. (Gen. Orchid. 4(1): 532. 2005) reported that the recent molecular and morphological phylogenetic analysis of the Eriinae by Ng (Phylogenetic relationships in tribe Podochileae (Orchidaceae: Epidendroideae): based on combined evidence from molecular and morphological data. Unpublished Ph.D. Thesis, University of London. 2002) provided further evidence suggesting that the large and unwieldy Eria, in the widely accepted sense, is polyphyletic. Combined ITS, matK, and trnL-F analysis shows the widely accepted Chinese genera Ceratostylis and Trichotosia to be nested within Eria s.l. Ng recommended the continuing recognition of these. However, former sections of Eria s.l. represented in China, viz. Bryobium, Callostylis, Conchidium, and a broadly defined Pinalia, are given generic rank. Eria sect. Aeridostachya J. D. Hooker, E. sect. Cylindrolobus (Blume) Lindley, and E. sect. Dendrolirium (Blume) Lindley form a clade and have been amalgamated into a very broadly defined Callostylis (Pridgeon et al., loc. cit.: 541-542. 2005). The constituent elements of Callostylis are, however, morphologically distinctive, and Aeridostachya, Cylindrolobus, and Dendrolirium are recognized as distinct genera in this account. Other changes affecting Chinese taxa include the inclusion of Eria sect. Pellaianthus J. D. Hooker into Campanulorchis (see p. 346) and E. sect. Strongyleria Pfitzer into Mycaranthes (see p. 348).

The genus Pinalia, established by Lindley in 1826, is newly circumscribed by Pridgeon et al. (loc. cit.: 569. 2005). It now comprises five former sections of Eria s.l., viz. E. sect. Hymeneria Lindley, E. sect. Pinalia (Buchanan-Hamilton ex D. Don) Lindley, E. sect. Polyura Schlechter, E. sect. Secundae Leavitt, and E. sect. Urostachya Lindley (see p. 352). This is significant because these taxa represent the majority of the former Eria s.l., altogether including approximately 160 species. The majority of taxa from China now belong within Pinalia.

Eria s.s. is represented by seven species in China. It is typified by the widespread E. javanica and comprises about half a dozen allied species mostly restricted to New Guinea, as well as the mainland Asian species formerly placed in E. sect. Trichosma (Lindley) Lindley, to which the remaining Chinese species belong and among which E. coronaria is the most widespread.

After publication of the family treatment for the Flora of China, one species was newly recorded from China (see HU Hao et al. 2010. J. Trop. Subtrop. Bot. 18(4): 401-402, i.e., Eria foetida Aver.).

About 15 species: mainland Asia and the whole of the Malay Archipelago, east to New Guinea and Bougainville Island; seven species (one endemic) in China.

(Authors: Chen Xinqi (陈心启 Chen Sing-chi), Luo Yibo (罗毅波); Jeffrey J. Wood)