same category. The 3-trace supply is more a characteris- 
tic feature of sepals than of stamens. From these consid- 
erations, the perianth of orchids seems to be more sepa- 
line in character. 
Ontogeny of the flower, in some cases, has been sought 
to elucidate the nature of the petals—whether they are 
akin to sepals or stamens. Thus Goebel (1933) correlates 
the belated appearance of petals during the ontogeny of 
the flower with their nearness to stamens. In the orchids 
the ontogenetic order of appearance of floral whorls is 
centripetal (Swamy, 1946; also unpublished data). And 
even when Goebel’s correlation is applied to the condi- 
tion in orchids, it is seen that the petals are not allied to 
stamens but to sepals. 
LaBELLUM. This structure of the orchid flower has 
been the target for much dispute. Brown (1831) put for- 
ward the doctrine that the labellum is acompound struc- 
ture resulting from the fusion of some of the staminal 
members with the lip. However, he did not offer sufh- 
cient evidence for his opinion and also was not certain as 
to which of the stamens enter into fusion. He further 
suggested that such a fusion was especially responsible 
for the extra-conspicuousness of the labellum with ridges 
and crests in some orchids. Lindley (1840) followed this 
view. Darwin (1899), after studying the course of vascu- 
lar traces in some orchids, came to the same conclusion: 
‘*The Orchid flower consists of five simple parts, namely, 
three sepals and two petals; and of two compound parts, 
namely, the column and labellum. The column is formed 
of three pistils and generally of four stamens, all conflu- 
ent. The labellum is formed of one petal with two pet- 
aloid stamens of the outer whorl, likewise completely 
confluent.’’ As Darwin thus elaborated and confirmed 
Brown's ideas, the authorship of the compound theory 
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