Ophrydinae 3 1 (LP)+4 (DS, LS, MP, 
(Fig. 2B) LS)+1 (LP) 
Vanilla, Dendrobium, 3 2 (LP, DS)+2 (LP, LS) 
Rhynchostylis, Aerides, ete. +2 (MP, LS) 
(Fig. 2C) 
Oberonia, Bulbophyllum, 3 3 (LP, LS, MP)+1 (DS) 
Coelogyne, Pholidota, +e (LP, LS) 
ete. (Fig. 2 D) 
Cymbidium, Eulophia, 4 3 (LP, LP, LS)+3 (MP, 
Spathoglottis, some LS, DS) 
members of Sarcanthinae, 
etc, (Fig. 2 E) 
From the preceding account it will be clear that, from 
the standpoint of the origin of traces, there is no basis 
for distinguishing the main traces that belong to the 
outer whorl from those that belong to the inner whorl 
of the perianth. Actually, the bundles of the inflores- 
cence axis that enter the flower split up in a variety of 
methods and constitute the six main traces of the ovary. 
Neither does there seem to be anything in the position 
of the traces themselves to distinguish the two whorls, 
because in transverse sections the six main bundles are 
arranged more or less on one and the same circumference 
(Fig. 8 A). There is also no difference between the traces 
of the two whorls with respect to size or degree of ex- 
pression. Even those main traces that adjoin the placen- 
tae (LP, Fig. 8 B), which in other groups usually show 
an exaggerated development either in size or prolifera- 
tion, in this case look exactly similar to the traces lying 
on alternating radii (DS, Fig. 3B). 
In some orchids with large-sized labellum (like Cym- 
bidium, Hulophia, Spathoglottis, ete.) the main trace 
underlying this modified petal (MP) shows a double na- 
ture (Fig. 2). It may be argued by some that this 
feature may be due to the size-relation of the organ which 
it is supplying. The weight of this argument becomes 
[ 68 | 
