sometimes AY or A8 or even a8 may be represented by 
the corresponding staminodal outgrowths externally or 
by vascular traces internally. 
(2) In the Ophrydinae it has been shown here that Al 
alone manifests itself as the functional stamen and that 
no other stamens are represented even by vascular traces. 
(3) In the remainder of the members of the Monan- 
drae, as arule, Al is the functional stamen, al and a2 
or sometimes A2 and A838, being present as traces. The 
origin and course of the various staminal traces (except- 
ing the one pertaining to A1) may be somewhat irregular 
in some advanced genera. ‘They may be quite clear in the 
juvenile condition of the flower but later become oblit- 
erated, or they may be ‘‘compound’’ from the very 
beginning. In the majority of the genera, however, all 
of the four lateral stamens are represented by the ‘‘com- 
pound”’ traces, al+A2 and a2+A38. 
(4) The expression of a8, though rare, can still be 
seen in some instances. 
The above facts, when considered from an ‘‘over-all’’ 
point of view, account for the presence of all of the six 
stamens belonging to the two whorls. At one time, per- 
haps, all of the six stamens were functional. During 
phylogenetic specialization, the median one of the inner 
whorl (a) disappeared early, probably in correlation with 
the differentiation of the labellum. Subsequently, the 
elimination of the lateral stamens of the outer whorl! was 
effected first and of the inner whorl later; this is sug- 
gested by the more frequent predominance of the latter 
and the less frequent expression of the former among the 
orchids here studied. However, when the vascular traces 
of the lateral stamens of both the whorls are present, 
they form ‘‘compound”’ traces as al+A2 and a2+A3. 
[ 90 | 
