Eria Lindl.,
Edwards's Bot. Reg. (1825) t. 904
Sympodial epiphytic or terrestrial plants with very short to long rhizomes, usually with thin, brown, hairy roots. Pseudobulbs present or not, consisting of one to many nodes, one- to several leaved, or, when absent, stems short to elongated, one- to many-leaved. Leaves sheathing at the base or not, arranged in two rows, sheath glabrous or hairy, blade glabrous, rarely with marginal hairs, plicate or duplicate, dorso-ventrally flattened, sometimes terete or [not in Thailand and Indochina] laterally flattened, deciduous, convolute or not, leathery, sometimes rather thin-textured. Inflorescence lateral or terminal, a raceme or carrying a single flower, very rarely a panicle, often hairy, usually arising from a small cavity in the stem. Flowers small to medium-sized, resupinate or not. Sepals free. Petals free, usually not very dissimilar to the dorsal sepal. Lip without spur, mobile or not. Column-foot present. Pollinia 8, solid, caudicles present or absent, stipe absent, viscidium present or absent.
Distribution
Sri Lanka, tropical continental Asia, Malaysia, Indonesia, the Philippines, Papua New Guinea, Australia, Pacific islands, east to Tahiti. About 375 species; in New Guinea c. 40 species.
Habitat
Epiphytes in lowland and montane forest.
Notes
An extremely diverse genus, in this respect among Asian orchid genera surpassed only by Dendrobium and Bulbophyllum. What is here still called Eria in the broad sense is in fact a conglomerate of several genera, which, based on DNA studies by Yan Peng Ng and others, will be split up in the near future, mainly along the lines of the currently recognised sections. The following sections have representatives in New Guinea (see Key below):
Aeridostachya
Aporodes
Bambusifolia (doubtful)
Cuneilabium
Cylindrolobus
Eria (syn. Goniorhabdos Schltr.)
Hymeneria
Mycaranthes
Polyura
Strongyleria
Urostachya (doubtful)
Of these, only section Eria can be said to have evolved truly distinctive forms in New Guinea, while most members of the other sections more or less closely resemble species found elsewhere, e.g. in Borneo and the Philippines. In contrast to Dendrobium, very few Erias possess showy flowers, while most are fairly unattractive. For this reason they are rather infrequently seen in cultivation.
Key to the sections of Eria in New Guinea
1a Pseudobulbs consisting of one internode. Leaves convolute, plicate ... sect. Eria
1b Plant without pseudobulbs, or pseudobulbs consisting of more than one internode. Leaves conduplicate, not plicate ... 2
2a Stems not swollen into pseudobulbs, more or less leafy throughout their length ... 3
2b Stems swollen into pseudobulbs, leafy in the apical part ... 6
3a Leaves laterally flattened ... sect. Aporodes
3b Leaves dorso-ventrally flattened ... 4
4a Inflorescences (sub)terminal, many-flowered, with inconspicuous floral bracts ... 5
4b Inflorescences lateral, few-flowered, with large floral bracts ... sect. Cylindrolobus
5a Inflorescences fascicled from the upper leaf axil. Lip with mealy callosities ... sect. Mycaranthes
5b Inflorescences not fascicled. Callosities on the lip, if any, not mealy ... sect. Bambusifolia
6a Pseudobulbs covered with large, patent, coriaceous sheaths. Lip entire, withour keels or calli, shorter than the column ... sect. Aeridostachya
6b Pseudobulbs covered with membranous, closely appressed sheaths. Lip entire or lobed, with or without calli or keels, as long as or longer than the column ... 7
7a Lip without keels, 3-lobed, with a large midlobe and very small lateral lobes at the base ... sect. Urostachya
7b Lip, if 3-lobed, with keels and lateral lobed not basal, or lip entire ... 8
8a Pseudobulbs narrowly conical, tapering towards the apex. Inflorescence very short; flowers fleshy ... sect. Strongyleria
8b Pseudobulbs cylindrical to clavate. Inflorescence short to elongated; flowers thin-textured ... 9
9a Lip entire, without keels or callosities, or with two short basal ridges ... sect. Polyura
9b Lip 3-lobed, with distinct keels often extending to near the apex, or with callosities ... 10
10a Pseudobulbs 1-leaved ... sect. Cuneilabia
10b Pseudobulbs 2- to several-leaved ... sect. Hymeneria