Chap. VIII. FLOWERS OF OKCHIDS. 237 



labellum ; and seven run up the great central column. 

 These vessels are arranged, as may be seen, in rays 

 proceeding from the axis of the flower ; and all on the 

 same ray invariably run into the same ovarian group ; 

 thus the vessels supplying the upper sepal, the fertile 

 anther (Aj), and the upper pistil or stigma (i. e. the 

 rostellum S,.), all unite and form the posterior ovarian 

 group. Again, the vessels supplying, for instance, the 

 left lower sepals, the corner of the labellum and one 

 of the two stigmas (S) on the same side, unite and form 

 the antero-lateral group; and so with all the other 

 vessels. 



Hence, if the existence of groups of spiral vessels 

 can be trusted, the flower of an Orchid certainly 

 consists of fifteen organs, in a much modified and 

 confluent condition. We see three stigmas, with the 

 two lower ones generally confluent, and with the upper 

 one modified into the rostellum. We see six stamens, 

 arranged in two whorls, with generally one alone (Ai) 

 fertile. In Cypripedium, however, two stamens of 

 the inner whorl (a^ and a^) are fertile, and in other 

 Orchids these two are represented more plainly in 

 various ways than the remaining stamens. The third 

 stamen of the inner whorl (^3), when its vessels can 

 be traced, forms the front of the column: Brown 

 thought that it often formed a medial excrescence, 

 or ridge, cohering to the labellum ; or, in the case of 

 Glossodia,* a filamentous organ, freely projecting in 

 front of the labellum. The former conclusion does 

 not agree with my dissections; about Glossodia I 

 know nothing. The two infertile stamens of the outer 

 whorl (A2, A3) were believed by Brown to be only 

 occasionally represented, and then by lateral excre- 



* See Brown's observations ' Plantsa Asiatiose rariores,' 1830, 

 •under Apostasia in Wallich's p. 74. 



