BOTANICAL MUSEUM LEAFLETS 
HARVARD UNIVERSITY 
Q 
CampripGr, Massacnuserts, June 30, 1934 VoL. 2, No. 6 
STUDIES IN STELIS. II. 
BY 
OakES AMES 
AmonaG the genera of the Pleurothallidinae the genus 
Stelis has been considered a very natural one, character- 
ized by unmistakable peculiarities in the structure of the 
gynostemium and by a clearly diagnostie perianth. But 
in the group discussed in the preceding paper of this series 
the stigmas, as already stated, exhibit a conspicuous de- 
parture from the typical condition and represent a tran- 
sitional trend toward Pleurothallis. Indeed, the type 
species of Pleurothallis, namely P. ruscifolia (Jacq.) 
R. Br., has a gynostemium that bears some resemblance 
to the gynostemium of Stelis rubens, differing chiefly 
from it in being obliquely truncate and unlobed, but re- 
sembling it in having the stigmatic orifice extending along 
the summit on the anterior edge. This peculiarity is very 
strongly marked in a Costa Rican species of Stelis that 
has not yet been described and which may be character- 
ized as follows: 
Stelis pendulispica Ames, sp. nov. 
Herba verisimiliter caespitosa. Caules secundarii 
elongati, erecti, monophylli, vaginis amplis vestiti. Fo- 
lium oblongo-ellipticum, valde coriaceum, usque ad basin 
attenuatum, in petiolum sulcatum elongatum contrac- 
tum. Pedunculus plus minusve erectus, cum racemo fo- 
lium excedens. Racemus elongatus, multiflorus, pendu- 
[85 | 
