A new species of Corybas (Orchidaceae) from Papua New Guinea

Herba parva erecta, 1—3(—7) cm alta. Tuber globosum, 4—6 mm diam., albidum aut dilute brunneum, subtiliter villosum. Rhizomata atque pars subterranea albida. sparse villosa. Pars supraterranea caulis dilute viridis, glabra, ad basim per unicam vaginam tubularem inclusa. Vagina 8—12 mm longa, uninervis, distaliter paululum expansa, ultimo discreta per 1—2 mm, pars discreta acuminata, apice cirriformi. Caulis semiteres 1—7(—10) cm longus. Folium ovatum aut elliptico-ovatum, 1.5—3(— 6) per 1—1.5(—2) cm latum, supra pallide viride, infra pallidius, apex anguste acuminatus, basis breve attenuata atque in duas costas caulem decurrens, costa supra impressa, infra manifeste elevata, nervi basales utroque latere 1, convergati, nervi supra basales 4 ad 6 utroque latere, laxe scalariformiter reticulati, venae marginales absunt. Pedicellus teres, 2—4 mm longus, glaber, per unicam bracteam subtentus. Braclea linearis, canaliculata, (5—)10—17 per 2—3 mm, dilute viridis, anguste acuta, uninervis, glabra. Ovarium ascendens, atque paululum inflexum, cylindricum, 6—10 per 2—3 mm, viridi-albidum, tortum, 6-sulcatum, glabrum. Sepalum medium erectum, spathulatum, 20—30 mm longum in totum, 7—9- nervatum, albidum, virgis angustis rubidis 5 ad 7 secundum nervas medias lateralesque praeditum, unguis anguste attenuatus, canaliculars, 10—15 mm longus, lamina ovata, 10—15 mm per 7—14 mm, margine vix aut non inflexo, integro, apice obtuso. Sepala lateralia reducta. subulata, 3—6 per 0.5 mm, subviridia, uninervia, glabra. Petala lateralia discreta, erecta atque paululum reflexa, linearia, acuta, 15—30 per 2—3 mm, ad bases albido-viridia, distaliter gradatim ad rubida fuscantia, ultimo erythronigra ad apices, uninervia, glabra. Labium erectum, infundibulare, abrupte reflexum atque ad limbum horizontaliter expansum, 15—20 mm longum in totum, ad basim conspicue bicalcaratum, calcaria 2—3 mm longa, tubus 10—15 mm longus in totum, dorsaliter per totam longitudinem conspicue inflatus. parte inflata longitudinaliter carinata et lateraliter valde compressa, tubus basi viridis ad viridi-albidus, in parte media gradatim ad viridi-brunneum fuscans, partes superiores tubi faucisque porphyreobrunneae, maculis brunneis irregulariter dispositis praeditae, limbus latecordatus, 8—12 per 7—10 mm, apice obtuso, deflexo, margine inflexo, membranaceo, irregulariter fimbriato-laciniato, parte limbi centrali in umbonem hemisphericalem, 6—10 mm latum, 1—2 mm altum expansa, umbo, faux et pars limbi interior purpureo-nigra, laxe minuteque pubescens, limbus externe viridi-albidus, maculis brunneis irregulariter signatus, glaber. Columna erecta, 2 mm longa. Fructus non observatus. Small, erect herb, 1—3(—7) cm tall. Tuber globose, 4—6 mm in diameter, white or light brown, finely villose. Rhizomes and subterranean portion of the stem white, scattered villose. Above ground portion of the stem light green, glabrous, enclosed at the base by a single, tubular sheath. Sheath 8—12 mm long, 1-nerved, slightly flared distally, ultimately free for 1—2 mm, free portion acuminate, apex cirriform. Stem semiterete, 1—7(—10) cm long. Leaf ovate or elliptical-ovate, 1.5—3(—6) by 1—1.5(—2) cm, light green above, paler below, apex narrowly acuminate, base shortly attenuate and decurrent into 2 ribs of the stem, midrib impressed above, prominently raised below, nerves 2 on either side of the midrib, convergate, suprabasel nerves 4 to 6 on either side of the midrib, laxly scalariform reticulate, marginal veins absent. Pedicel terete, 2—4 mm long, glabrous, subtended by a single bract. Bract linear, channelled, (5—)10—17 by 2—3 mm, pale green, narrowly acute, 1-nerved, glabrous. Ovary ascending and slightly inflexed, cylindrical, 6—10 by 2—3 mm, greenish-white, twisted, 6-grooved, glabrous. Median sepal erect, spathulate, 20—30 mm long overall, 7—9-nerved, white with 5—7 narrow maroon bands running along the mid and lateral nerves, claw narrowly attenuate, channelled, 10—15 mm long, blade ovate, 10—15 mm by 7—14 mm, margin slightly or not inflexed, entire, apex obtuse. Lateral sepals reduced, subulate, 3—6 by 0.5 mm, light green, 1-nerved, glabrous. Lateral petals free, erect and slightly reflexed, linear, acute, 15—30 by 2—3 mm, whitish-green at the base, darkening gradually to maroon distally, ultimately becoming reddish-black at the tips, 1-nerved, glabrous. Lip erect, infundibular, abruptly reflexed and expanded horizontally at the limb, 15—20 mm long overall, conspicuously bicalcarate at the base, spurs 2—3 mm long, tube 10—15 mm long in all, conspicuously inflated dorsally along its entire length, inflated portion longitudinally keeled and strongly compressed laterally, green to greenish-white at the base, gradually darkening to greenish-brown medially, upper portions of the tube and throat purple-brown with irregularly spaced brown blotches, limb broadly cordate, 8—12 by 7—10 mm, apex blunt, deflexed, margin inflexed, membranous, irregularly fimbriate-laciniate, central portion of the limb expanded into a hemispherical boss, 6—10 mm wide by 1—2 mm tall, boss, throat and interior of the limb purple-black, laxly, minutely pubescent, limb externally greenish-white, irregularly marked with brown blotches, glabrous. Column erect, 2 mm long. Fruit not seen