1954] 



PLANTS COLLECTED IN NYASALAND 



81 



visae. lnflorescentiae simpliciter racemosae, pluri- ad multi florae. Flores parvuli, 

 glabri vel pubescentes, labello perlato ecalloso ± dense farinaceo-pubescenti. 



Species 2 adhuc notae, Africae orientalis indigenae. Species typica sectionis, 

 P. eurychila Summerh. 



When I described P. eurychila (Kew Bull. 1939, 492) I pointed out that it lacked 

 the prominent hair-cushions on the lip which are such a striking feature of sect, 

 Elasticae in which I had placed it. I also drew attention to the fact that it was the 

 only species of the section known from eastern Africa. The discovery of a further 

 species, described below, from Nyasaland, agreeing with P. eurychila in many 

 important features, has confirmed my suspicions that the latter is not properly 

 placed in sect. Elasticae. I am therefore creating a new section to contain the 

 two species. The new section shows certain affinities in habit and floral struc- 

 ture with the predominantly East African sections Isochiloideae and Dendrobi- 

 anthe. It differs from the former in the general floral structure, particularly the lip 

 shape, and in the absence of capitate or clavate hairs, and from the latter in the 

 different inflorescence, firmer texture of the flowers, and lip shape. 



Polystachya brassii Summerh., sp. nov. 



Affinis P. eurychilae Summerh., a qua statura multo minore, inflorescentiis 

 paucifloris, sepalis pubescentibus mento pro rata breviore, labelli lobo intermedio 

 majore, ovario dense pubescenti satis differt. 



Herba nana, epiphytica vel saxicola, sub anthesi aphylla. Caules approximati, 

 erecti, 1.5" 3 cm. alti, inferne in pseudobulbos conicos vel ovoideos 3" 11 mm. al- 

 tos incrassati, foliorum vaginis paleaceis demum in fibras solutis imbricantibus 

 omnino dbtecti, basi radices flexuosas ramosas graciles griseas emittentes. Folia 

 juvenilia tantum visa; lamina i 3 mm. longa, apice rotundata. lnflorescentiae sim- 

 pliciter racemosae, circiter 10 mm. longae, 4-5-florae; pedunculus vaginis 1-2 

 lanceolatis acutis i hyalinis instructus; rhachis i 5 mm. longa, dense pubescens; 

 bracteae lanceolatae vel ovatae, cuspidato-acuminatae, 1.5-3 mm. longae, t hya- 

 linae, glabrae. Flores patentes vel erecto-patentes, purpureo- vel viridi-albi, la- 

 bello flavido; pedicellus cum ovario 2-3 mm. longus, dense patentim pubescens. 

 Sepalum intermedium ellipticum vel elliptico-ovatum, apice obtusum vel rotunda- 

 turn, 4.5-5 mm. longum, 2.5-3.25 mm. latum; sepala lateralia oblique ovata, apice 

 acuta vel obtusa, margine antico (superiore) circiter 6 mm. longa, basi 2.75-3.25 

 mm. lata, cum pede columnae mentum obtusum 1.75-2.5 mm. longum formantia; se- 

 pala omnia extra sparse pubescentia, quinquenervia. Petala oblonga vel sub- 

 spathulato-oblanceolata, obtusa, 4-5.25 mm. longa, 1.25-2 mm. lata, uni- vel sub- 

 trinervia, glabra. Lahellum ex ungue brevissimo ambitu ± transverse oblongum vel 

 ellipticum, antice trilobatum, totum 4.75-5.5 mm. longum, 7-7.5 mm. latum, margi- 

 nibus exceptis X dense farinaceo-puberulum vel pubescens, ecallosum; lobus in- 

 termedius semi-orbicularis, rotundatus, 1.75-2 mm. longus, 3"3.3 mm. latus; lobi 

 laterales patentes vel leviter incurvati, semi-orbiculari-oblongi, rotundati, antice 

 circiter 2 mm. longi. Columna erecta vel + incurvata, subteres, 2.5-3 mm. alta, 

 androclinio leviter excavato; anthera hemisphaerica, antice haud producta; pollinia 

 4, ovoidea vel oblonga, per paria arete compressa, 1-1.25 mm. longa, viscidio fere 

 orbiculari 0.75 mm. lato; fovea stigmatica quadrata. 



Kota-kota District: Chenga Hill, amongst dry mosses and lichens on a shaded 

 rock, sepals very pale purple, petals white, lip yellowish-green edged with white, 

 1600 m., Sept. 9, 1946, 17604 (TYPE); among mosses and lichens on a dry shaded 

 rock, flowers greenish- white, 17605. Cholo District: Cholo Mountain, epiphytic 

 on exposed trunk of rain-forest tree, sepals purplish-white, petals white, lip pale 

 yellow edged with white, column green, 1200 m., Sept. 26, 1946, 17830. 

 Nyasaland. 



