464 Scientific Proceedings, Royal Dublin Society^. 



two anomalies in the supply of the vessels to the different parts. 

 Those are : first, that the vessels which supply the sides of the 

 upper sepal enter the postero-lateral or paired petal bundles ; and, 

 secondly, that the vessels to the anterior side of the upper petals 

 enter the antero-lateral or paired sepal groups. 



I have examined both longitudinal sections of the flowers ren- 

 dered transparent, and a consecutive series of transverse sections, 

 and I am able to confirm Mr. Darwin's statement that the lateral 

 sepaline bundles join the paired petal bundles. Ramification of 

 the sepal bundles occurs, while the ultimate paired petal bundle 

 remains unchanged after giving off the bundle to the sepal. It 

 seems remarkable that the position of the bundle of vessels to 

 the so-called anterior parts of the upper or paired petals should 

 not have led Mr. Darwin to consider the structures to be staminodes, 

 as they are in the proper position. 



I can trace no vestige of bundles to the three rudimentary 

 stamens of the inner row, if such they be, although I have spe- 

 cially searched for them. 



In making sections of the inferior ovary, six bundles can be 

 observed — three corresponding to the placentas and three alternat- 

 ing with them. Two of the placental bundles have each three minute 

 bundles on their inner side, and the third, corresponding to the 

 labellum, has two large bundles. These eight small bundles quite 

 disappear in the upper part of the ovary, and the shortest placenta 

 is that corresponding to the position of the labellum. We thus have 

 in this Orchid flower three bundles which have to supply the pla- 

 centas, and three that do not. The bundles supplying the pla- 

 centas must be called upon to supply water and much nutrient 

 matter to the growing ovules, and their development in the flower 

 above must be hindered. Hence, as they correspond to the petals, 

 the petals will be feeble in Orchid flowers, and the stamens super- 

 posed to the petals more or less completely wanting. On the other 

 hand, the sepaline bundles are well developed, and they give off 

 bundles to the fertile stamens and lobes of the stigma, the bundles 

 to the stigmas being given off very early before those to the lateral 

 stamens. The Orchid flower is much developed anteriorly and pos- 

 teriorly; but the posterior petal, the labellum, cannot get much 

 nourishment from a bundle which has to sujDply the placenta, and 

 therefore its supply must be supplemented. In the leaves of mono- 



