suppression of a different staminal circle. This suppres- 
sion seemingly conveys the idea that Neuwiedia gave 
rise simultaneously to both Cypripedioideae and to the 
monandrous orchids. However, the sum total of charac- 
teristics which make up the monandrous orchids suggests 
that during the course of evolution there were other lines 
besides that of Neuwiedia which fed into the complex. 
Although the general pattern of the monandrous orchids 
(which include 90% of the known species) can be ex- 
pressed by asingle diagram, the group itself is composed 
of three distinct units, depending on the manner and de- 
gree by which the individual pollen grains adhere to 
each other to form the pollinia. These three groups are: 
Neottiowdeae, Ophrydoideae and Kerosphaeroideae. 
In Neottioideae and Ophrydoideae (text fig. 1) the pol- 
len grains are of a soft consistency and cohere into massu- 
lae in arelatively loose manner; in the former unit they 
easily separate into a fine powdery mass (sectile pollinia), 
while in the latter they form large granules (granular 
pollinia). In Kerosphaeroideae the cohesion of the indi- 
vidual grains is so compact that the pollinium may be 
broken only through the exertion of considerable force. 
The presence of pollinia is characteristic of the three 
units of monandrous orchids only. In the 4 postasioideae 
NEOTTIOIDEAE OPHRYDOIDEAE KEROSPHAEROIDEAE 
