It is Type III that presents an interesting series of 
increasing complexity. The latter is intimately associated 
with anastomoses, cohesion and adnation of the individu- 
al vascular traces of the flower. The increasing trend of 
complexity of perianth members is seen in the derivation 
of marginal traces of the perianth members of one whorl 
from those of the other and their anastomoses. As a re- 
sult of this, the places of origin of the staminal traces 
become highly displaced and carried to higher levels, 
until the adjacently placed lateral staminal traces form 
‘compound’ traces, here designated as al A2 and a2 
+A8. The effect of adnation on the different whorls of 
the flower has been described in detail. 
The inferior ovary is looked upon as due to an extreme 
adnation of the different floral whorls. The outer and 
inner whorls of the perianth, though externally distinct 
from one another, present the same anatomical features 
and on this account the inner whorl is considered to be 
more sepaline than otherwise. The labellum is also shown 
to receive the same vascular supply as the rest of the peri- 
anth members; it is stressed that there is no evidence to 
consider it to be a compound structure, as was thought 
by Brown and Darwin. 
The two lateral stamens of the outer whorl which were 
thought by Darwin to have fused with the labellum, are 
here shown to be represented in the gynostemium, either 
as individual traces (A 2 and A8) or in their ‘‘ecompound’”’ 
manifestations (al+A2 and a2+A3), whenever they are 
present. It has also been shown that the median stamen 
of the inner whorl is capable of expressing itself occa- 
sionally. 
It is suggested that in the ancestral orchid flower all of 
the six stamens were functional; that in course of time 
the posterior three ceased to be functional and that it 
seems as if such a progenitor may have given rise to the 
[98 | 
