M'Nab — On the Structure of the Fhtoer of Boimtea speciosa. 465 



cotyledons the bundles entering the leaf are directly proportional to 

 the circumference of stem occupied by the leaves, and to the number 

 of bundles in the stem. In the Orchid ovary the posterior part is 

 flattened in Bonatea, and this evidently permits an additional supply 

 of nourishment to be obtained from the more vigorous lateral sepa- 

 Kne bundles, the petaline bundles not even being able to send off 

 a filament to the extremely reduced structures in the flower which 

 obviously represent two at least of the inner verticil of stamens. 

 Thus, many of the peculiarities of the Orchid flower probably de- 

 pend upon the vascular supply, and this subject is one that will 

 certainly well repay further careful research. 



The flower of Bonatea sjjeciosa is well described and figured by 

 Mr. Roland Trimen, in Jour. Linn. Soc, vol. ix., p. 156 ; but he 

 gives no critical remarks on the structure of the flower. 



2 S2 



