ORCHIDACEiE 



arcuatus. Sepala lateralia 4.75 mm. longa, infra medium 2 mm. 

 lata, prope basim cohaerentia, fere libera, anguste triangula vel 

 triangulari-lanceolata, obtusa, extus leviter carinata, trinervia. 

 Sepalum dorsale 5 mm. longum, 2.25 mm. latum prope basim, 

 ovato-lanceolatum, obtusum, trinervium. Petala 1.5 mm. longa, 

 apice 1 mm. lata, valde incrassata, cuneata, truncata, extus levi- 

 ter umbonata prope apicem, in sectione transversa triangula- 

 ria, .5 mm. in crassitudine. Labellum 1 mm. longum, basi .75 mm. 

 latum, supra medium dilatatum 1 mm. latum, orbiculari-apicu- 

 latum, a basi breviter oblonga usque ad medium labelli callo bi- 

 lobato, antice excavato extendit. Columna brevis, apicem versus 

 dilatata, petala aequans, apice bilobulata. 



In habit this species suggests S. micrantha Sw. The callus on 

 the labellum resembles that of S. patula Schltr. The aspect of 

 the flowers recalls some species of Pleurothallis. 



Colombia, State of Cauca, Paramo de Buena Vista, Huila group, Central 

 Cordillera, H. Pittier 1156, January 1906. Upper zone of forest. 3000— 

 3600 meters altitude. (Type in U. S. Nat. Herb. No. 531353.) 



Stelis Williamsii Ames sp. nov. AiF. S. confusae Schltr. 

 Radices fibratae, copiosae, patentes. Caules caespitosi, abbrevi- 

 ati, vix 1.5 cm. longi, monophylli, oblique ascendentes, in sicco 

 longitudinaliter sulcati. Folia coriacea, in petiolum abbreviatum 

 sensim decrescentia, cum petiolo 4-10 cm. longa, usque ad 11 

 mm. lata, ligulata, marginata, apice retuso-apiculata, subtus 

 nervo medio leviter carinato. Scapus singulus, folio longior, us- 

 que ad 2 dm. longus, infra racemum paucibracteatus. Bracteae 

 acutae, plus minusve 6 mm. longae, vaginantes. Racemus multi- 

 florus, usque ad 9 cm. longus. Rachis gracilis, in sicco fragilis, 

 floribus 3-5 mm. inter se distantibus. Bracteae inflorescentiae 

 triangulari-ovatae, plus minusve 3 mm. longae, acutae, extus 

 longitudinaliter carinatae. Pedicellus cum ovario 2 mm. longus. 



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