Cymbidium, ete.), both sets of lateral stamens (A2, A3 
and al, a2) may be present. It must be stated here that 
the expression of the staminal traces is highly variable in 
different genera and is often associated with highly com- 
plicated types of adnation. (This phenomenon is treated 
in detail in a later part of this text under ‘‘Comparative 
Resumé of the Vascular Supply of the Stamens.’’ See 
page 77). After supplying the vasculature to the stamens 
and stigmas, the residue of the main traces (excepting the 
one under the dorsal sepal) breaks up further to constitute 
the vascular traces of the perianth lobes. (Variations of 
the vasculature of the perianth members of this type are 
explained ina later part of this text under ‘‘Comparative 
Resumé of the Vascular Supply of the Perianth.*’ See 
page 76). 
The following points may be noted in connection with 
this type: 
1. ‘The gynostemium (Fig. 4 I) contains the following 
traces: 
a. Al supplying the median stamen of the outer whorl, which 
is the functional one, 
b. G1, G2 and G8, reaching the rostellum and the confluent 
lateral functional stigmas, and 
c, either al and a2 representing the traces of the lateral stamens 
of the inner whorl, or A2 and A8% representing the lateral 
stamens of the outer whorl, or both. 
2. The traces of the staminal and stigmatic whorls are 
all embedded in a well-developed pillar-like structure 
(a gynostemium). 
Types I and II are consistent; no marked variations 
were seen. But Type III is subjected to a high degree 
of plasticity. This is closely associated with increasing 
cohesion, adnation and other phenomena which are de- 
scribed in the following paragraphs. 
[ 75 | 
