microtome sections alone can reveal its incipient condi- 
tion anatomically. In all of the other orchid flowers stud- 
ied at this time the structure is well-developed; and in 
all such species, it is an appendicular structure containing 
the vascular traces supplying the staminal and stigmatic 
whorls. The morphological apex of the flower, therefore, 
does not extend to the apex of the gynostemium but 
ceases at the point of the insertion level of the perianth. 
Thus, in one and the same ‘‘floral tube’’ (as designated 
by Wilson and Just, 1939) of orchids, different degrees 
of adnation are seen, the ovary proper containing the 
fused vascular traces of all of the floral whorls and the 
gynostemium proper in which the individual traces of the 
stamens and stigmas are embedded. 
STAMENS. Robert Brown (1831) was the first to state 
in clear terms that the stamens in the orchid flowers are 
arranged in two alternating whorls, each whorl contain- 
ing three stamens. Since then Darwin’s investigations 
(1899) on several other orchids have brought to light a 
certain amount of evidence to support Brown’s views. 
But as Darwin also believed that the lateral stamens of 
the outer whorl were fused with the labellum, he con- 
templated that only the lateral stamens belonging to the 
inner whorl were always present in the gynostemium. 
It is not so easy to determine which particular trace 
represents which particular stamen just by observing a 
section of the gynostemium. ‘*‘Compound’”’ staminal 
traces have been demonstrated in the present study as a 
very common condition in orchid flowers. Some other 
salient points concerning the vascular supply to the sta- 
mens may now be recalled: 
(1) In the Cypripedilinae, al and a2 are normally 
present and are functional. AJ1 is transformed into a 
staminode. In teratological flowers (see Worsdell, 1916) 
[ 89 | 
