ORCHIDACEAE
Porpax Lindl., Edwards’s Bot. Reg.: 31(Misc.): 62. (1845).
By: Devendra M. Bajracharya
Taxon Description
Plant dwarf, epiphytic or lithophytic, tiny, clump-forming herb. With or without a rhizome. Pseudobulbs crowded, dorsiventrally compressed, flattened globose, covered fine fibrous reticulate or not, without conspicuous nodes. Leaves 1-4, emerging after flowering or not, petiolate or sessile, apiculate with or without seta at the apex. Inflorescence terminal, one to flowers, borne at apex of pseudobulbs, peduncle short, cylindrical or filiform, erect, glabrous, floral bracts conspicuous. Flowers tubular or not, white or orange-red to deep dull red, sometimes flushed with greenish yellow. Pedicel and ovary glabrous. Sepals unequal, forming tube or not, forming a distinct mentum with column foot or absent. Petals spatulate to oblong, narrow, smaller and shorter than sepals, sometimes hairy or absent. Lip entire or obscurely 3-lobed, completely or incompletely enclosed in tube, margin erose to finely dentate, disk with or without a basal callus or keels. Column short, minute; pollinia 8, rostellum rather large, truncate. Capsules pyriform or globose to obpyriform or obovate-oblong or angular.
Taxon Statistics
Worldwide about 11 species: distributed in mainland Asia, Nepal, China, and India through SE Asia. Five species in Nepal.
Key to Species
1a Pseudobulb flattened, globose or sub globose.Inflorescence 1 flowered …………………………………………………………………………………………………… 2
b Pseudobulb flask shaped. Inflorescence more than 1- flowered ……………………………………………………………………………………………………………………3
2a Leaves appearing after flowering. Flower dull purple-brown ………………………………………………………………………………………………………..1. P. elwsii
b Leaves appearing before flowering. Flower brown ……………………………………………………………………………………………………………………….3. P. meirax
3a Leaves with long seta. Inflorescence 1 or 2- flowered. Flower pale-white. …………………………………………………………………………………..5. P. pusilla
b Leaves without seta. Inflorescence 1 or 3 (-6) – flowered. Flower pale-green, yellow or white ……………………………………………………………………… 4
4a Inflorescence 4–6 flowered. Flower pale-green to yellowish ………………………………………………………………………………………………….4. P. parviflora
b Inflorescence1—flowered. Flower white ………………………………………………………………………………………………………………………………..2. P. extinctoria
1. Porpax elwesii (Rchb. f.) Rolfe, Orchid Rev. 16:8. (1908).
Eria elwesii Rchb. f., Gard. Chron. n.s.19: 402. (1883).
Plants epiphytic or lithophytic, 2–2.5 cm tall. Pseudobulb ca. 5 mm across, globose–turbinate to discoid, covered with fibrous membrane. Leaves 2, emerging, after flowering, elliptic-oblong, 1.7–2.7 x 0.3–0.7 cm, acute, mucronate, many veined, shortly petiolate. Inflorescence solitary Flower, peduncle short. cylindrical, ca. 1.5 mm long, pedicel and ovary 2–3mm. Floral bract ovate-lanceolate, 5–7 x 3–3.5 mm, erect, concave, acuminate, longer than ovary. Flower tubular, ca. 12 mm across, dull-purple-brown, pedicel and ovary 1.5 –2.5 mm long. Sepal 5.5–6 mm long, lobe triangular-ovate. Dorsal sepal 5.5–6 mm long, lobe triangular-ovate, 2–2.5 × 1.8–2.3 mm, margins slightly revolute. Lateral sepals connate nearly to apex, 10–12 mm, lobes triangular-ovate, 1.5–2 × 1.2–1.6 mm, base spurred. Spur oblong, ca. 2 mm long, retuse at apex, Mentum absent. Petals broadly ovate-elliptic, 4–5 x 2–2.5 mm, obtuse. Lip obscurely tri-lobed, ovate-lanceolate, 3.5–4 x 2.5–3 mm, minute, lateral lobed, rounded, erect, with triangular notch at apex, mid-lobe oblong to ovate-orbicular, tapering to a blunt apex, entire, 3-viened. Column 1–3 mm. Capsule not seen.
Distribution: Nepal, NE India, SE Asia.
Altitudinal range: 900-1800 m.
Ecology: Epiphytic on bark of tree or lithophytic on mossy rocks in tropical and subtropical forest.
Flowering: July to August.
2. Porpax extinctoria (Lindl.) Schuit.,Y.P. Ng & H.A. Pedersen, Bot. J. Linn. Soc.,186 (2): 199 (2018).
Dendrobium extentorium Lindl. in Edwards’s Bot. Reg. 21: 1756 (1835); Eria extinctoria (Lindl.) Oliver
Plants epiphytic 8 cm tall. Pseudobulbs 8—10 mm across, globose, depressed at the tip, with reticulate network. Leaves 1, lanceolate ca. 5 x 1 cm, absent when flowering, appear during rainy season, acute. Inflorescence solitary flower solitary, borne from the apical part of pseudobulb, peduncle 5–6 cm long, thin. Floral bract ovate-lanceolate, boat-shaped, ca. 1 x 0.5 mm, minute, acute, shorter than ovary. Flower ca. 0.8 cm across, white, with pink flush on the tip, pedicel and ovary ca. 4.5 cm long. Sepal ovate, 4–5 mm long, acute. Dorsal sepal ovate, ca. 4 x 3 mm, acute. Lateral sepals triangular, ca. 10 x 5 mm, acute, round or slightly notch mentum ca. 8 mm long. Petals oblong–lanceolate, 9 x 4 mm, obtuse. Lip 3-lobed, 9 x 8 mm, base and inner throat yellow, lateral lobes small, rounded, base of lip is tapering narrow, attached to the foot of the column, mid-lobe large orbicular to obcordate, bilobulate, disk with three obscure minute papillose hairy lines warty distally at the center of lip. Column ca. 1 mm. Capsules ca 5 x 2 mm, pyriform.
Distribution: Nepal, India, and SE Asia
Flowering: April – July
Ecology: Epiphytic on moss-covered tree trunks in damp, primary evergreen forests.
Altitudinal range: 500-600m.
3. Porpax meirax (C.S.P. Parish & Rchb. f.) King & Pantl., Ann. Roy. Bot. Gard. (Calcutta) 8: 114 (1898).
Cryptochilus meirax C.S.P. Parish & Rchb. f., Trans. Linn. Soc. London. 30: 148 (1874).
Plants epiphytic, 2–3 cm tall. Pseudobulb 8–10 mm across, clustered, depressed-turbinate, covered with a membrane having radiating longitudinal fibers. Leaves 2, elliptic-oblong, 5–7 x 2–2.5 mm, appearing after the flowers, obtuse, mucronate. Inflorescence solitary flower, borne from the apex of leafless pseudobulb, peduncle 2–3 mm short. Floral bract ovate-lanceolate, 5–7 x 3–3.5 mm, erect, concave, acuminate, longer than ovary. Flower tubular, ca. 12 mm, dull brown, glabrous, pedicel and ovary ca. 0.2 mm long. Sepals forming tube, ca. 8 mm long, united into sapal tube at apex, the free end of dorsal sepal curved upwards. Dorsal sepal free for almost half-way, 4–5 mm long.Lateral sepals united up to bifid mucronate apex 4–5 mm long, mentum absent. Petals oblique-ovate, acute and apiculate at apex, 3-4 mm long, 2 mm broad. Lip obscurely 3-lobed, ovate-lanceolate, ca. 4 x 2 cm, apex obscurely acuminate, the base with a triangular notch, lateral lobe round, erect with triangular notch at base, mid-lobe oblong, margin entire, tapering to a blunt apex. Column ca. 1 mm. Capsule not seen.
Distribution: Nepal, NE India, and SE Asia.
Altitudinal range: 800-1800 m.
Ecology: Epiphyte on bark of old tree or lithophytes on mossy rocks in tropical to subtropical forest.
Flowering: July to August.
4. Porpax parviflora (D. Don) Ormerod & Kurzweil, Phytotaxa 481(1): 215 (2021).
Dendrobium parviflora D. Don, Prod. Fl. Nepal: 34 (1825); Porpax muscicola (Lindl.) Schuit., Y. P. Ng & H.A. Pedersen; Eria muscicola (Lindl.) Lindl.; Dendrobium muscicola Lindl.
Plants epiphytic, 3–4 cm tall. Pseudobulbs 4—6 mm across, depressed globose to discoid, caespitose, with reticulate network. Leaves 3-4, ovate to obovate-oblanceolate, 3—4 x 0.3–0.4 cm, acute or apiculate, petiolate or sessile. Inflorescence 4-6 flowered, peduncle 1–2.5 cm, glabrous, glabrous. Floral bract ovate-lanceolate, 3–5 x 1.5 mm, acuminate, longer than ovary. Flower 3–4 x 1.5 mm, pale-green to yellowish, pedicel and ovary ca. 2 mm long. Sepal lanceolate, 5–6.5 mm long, entire, acuminate. Dorsal sepal lanceolate, 2–4 x 0.8–2 mm, acuminate. Lateral sepals ovate-lanceolate, 3–4 x 3 mm, falcate, entire, acuminate, mentum ca. 2 mm, subglobose. Petals narrowly lanceolate, 2–2.4 x 0.6–0.9 mm, thin, acuminate. Lip simple, narrow lanceolate, ca. 3 x 0.9–1 mm, acute, concave, slightly dilated and deflexed at the middle, erose, acuminate, apically with the minutely trilobulate or irregular teeth, two callus at the base of the disk. Column 1.5–2 mm. Capsules 3 — 6 x 1.5–2.8 mm, globose to obpyriform.
Distribution: Nepal, N India, China. S. Asia and SE Asia.
Altitudinal range: 500-3500m.
Ecology: Epiphytic on tree trunks in tropical and subtropical evergreen forest.
Flowering: July to August.
5. Porpax pusilla (Griff.) Schuit. Y.P. Ng & H.A. Pederson, Bot. Jour. Linn. Soc. 186: 200. (2018).
Conchidium pusillum Griff., Not. Pl. Asiat.3 :321 (1851); Eria pusilla (Griff.) Lindl.; Pinalia pushilla (Griff.) Kuntze
Plants epiphytic, 2–5 cm high. Pseudobulbs in pairs, 4–5 mm across, membranous sheaths. Leaves 2-3, ovate-lanceolate ca.1.6 x 0. 4 cm, apiculate with 0.5–3 mm long seta at the apex. Inflorescence apically 1 -flowered or rarely with another rudimentary flower, peduncle 1–3 cm, filiform, erect, glabrous. Floral bract ovate, 0.8–1 x 0.5 mm, acuminate, concave, longer than ovary. Flower ca. 6 mm across, creamy yellow with greenish tinge, glabrous. Pedicel and ovary ca. 1.5 mm. Sepals narrowly lanceolate, 2.5–4.5mm long, entire, acuminate. Dorsal sepal ovate, 5–6.5 x 2–2.5 mm, acuminate, glabrous. Lateral sepals lanceolate, 5–5.5 x 2.5 mm, triangular, acuminate, glabrous, mentum 5–8 mm, incurved. Petals lanceolate, ca. 4 x 2 mm, similar to dorsal sepal, acute, narrow, unequal. Lip simple, lanceolate, ca. 5 x 3 mm, apex finely rugose, slightly recurved, erose to fine dentate margin, disk with elongated to near middle with two longitudinal keels. Column 1.5–2 mm. Capsules 4–7 x 2.8 — 3.2 mm, obovate-oblong.
Distribution: E. Himalaya, Nepal, China and SE Asia.
Altitudinal range: 1300-1700 m.
Ecology: Epiphytic on moss covered tree trunks in evergreen forest.
Flowering: September –December.