In the remaining groups (Neottioideae, Ophrydoideae 
and Kerosphaeroideae) the entering three or two bundles 
already differentiate in the pedicel to supply the ovary 
with its six main traces. The pattern by which these six 
traces of the ovary proliferate in passing to the floral and 
sex organs is uniform throughout the family. The three 
dorsal bundles of the ovary enter directly into the three 
sepals, with a trace leading from each of them to the gyn- 
ostemium; an additional branch deviates from the main 
bundle which supports the dorsal sepal to the anther of 
the outer whorl. The three ventral bundles of the ovary 
enter directly into the petals, the two lateral ones giving 
rise to a trace which supports the anthers in the inner 
whorl. The main trace of the bract is also derived from 
one of the three incoming bundles. 
The presence of six undifferentiated bundles in the 
A postasioideae and Cypripedioideae, as contrasted with 
three or two in the monandrous orchids, is a further in- 
dication of the relative primitiveness of these two groups. 
Placentation. The ovary in the Orchid family is syn- 
carpous, either three- or one-carpellate (Plate IX). The 
three-carpellate condition, i.e. with axile placentation, is 
present in all species and genera of the 4 postasioideae, 
in Selentpedium and Phragmipedium of the Cypripedioid- 
eae and ina few genera of the Neottioideae (Lecanorchis, 
Kriaxis, etc.). The remaining genera of the Cypripedi- 
oideae and the monandrous orchids exhibit a monocarpel- 
late ovary, i.e. the placentae are parietal in origin. 
It is generally accepted that axile placentation is a 
more primitive condition than parietal, and its occur- 
rence in the Orchid family is limited to groups of re- 
spectively primitive status. 
Our knowledge with regard to the manner of transi- 
tion from axile placentation to the parietal type is very 
meager. ‘wo seemingly aberrant types, i.e. Phragmi- 
[ 65 ] 
