lanceolate-oblong, acute or minutely tridenticulate at the 
apex, narrowed to a short indistinct petiole, up to 7.8 
em. long and 1.25 em. wide, rigid and coriaceous in the 
dried specimen. Inflorescence solitary, about twice as 
long as the leaf, up to 13.8 cm. long, arising from near 
the apex of the stem where it is invested by a tubular 
membranaceous, long-acuminate sheath. Peduncle 4.7— 
8.7 cm. long, provided (in the middle or above) with 
a single short infundibuliform sheath. Raceme many- 
flowered, subdense above, rather lax below, secund. Flow- 
ers small, bilabiate, glabrous, rather fleshy, light green 
throughout. Dorsal sepal connate with the lateral sepals 
for about one third of the length, about 6.3 mm. long; 
free part broadly ovate, obtuse or subacute, 3-nerved, 
about 4.8 mm. long and 4.1 mm. wide. Lateral sepals 
shorter, entirely connate into a deeply concave and bas- 
ally saccate lamina which is 6-nerved lightly retuse and 
apparently suborbicular when expanded, nearly 6 mm. 
long and broad. Petals minute, transversely subquadrate- 
ovate, subacute at the broad fleshy-thickened apex, 3- 
nerved,about 1 mm. long. Lip very small,deeply concave, 
about 1.5 mm. long, ovate or rhombic-ovate with up- 
curved sides, obtuse or subacute, the lower half being 
wholly occupied (except near the margins) by a fleshy 
convex bilobed callus. Column very short and stout, 
about equaling the petals, dilated from the base, deeply 
3-lobed above. 
Stelis concaviflora differs from S. rhomboglossa Schltr. 
in having glabrous flowers and a dissimilar lip. It diverges 
from SS. pleurothalloides Ames in having connate lateral 
sepals and a different lip. 
Apurimac: Prov, Andahuaylas, Quebrada, north of Chincheros, at 
2800 meters altitude, among cliffs and on gravelly clay banks, ‘fl. 
light pale green throughout,’’ February 27, 1939, H. E. Stork & O. 
B. Horton 10765 (Tyrer in Herb. Field Mus. No. 1051119). 
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