Fecundation in Orchidece and Asclepiadea. 701 



In most other cases the anterior lobe, or that placed opposite 

 to the perfect stamen, and deriving its vessels from the same 

 cord, manifestly differs both in form and texture from the other 

 two. To this anterior, or upper lobe, as it generally becomes 

 in the expanded flower, the glands always belong to which the 

 pollen masses become attached, but from which they are in all 

 cases originally distinct, as may be proved even in Ophrydeae. 



According to my view, therefore, of the mode of impreg- 

 nation, its office is essentially different from that of the two 

 lateral lobes or stigmata, which in various degrees of develop- 

 ment are always present, and in all cases, when the ovarium is 

 perfect, are capable of performing their proper function. 



The greatest development of these lateral stigmata takes 

 place in the tribe of Satyrinae or Ophrydeae, as in many species 

 of Habenaria^ those especially which are found near or within 

 the tropics ; and still more remarkably in Bonaiea speciosa, a 

 plant hardly indeed distinguishable from the same extensive 

 genus. 



It would seem that in Bonatea the extraordinary development 

 and complete separation of these lateral stigmata, have effec- 

 tually concealed their true nature ; and accordingly they have 

 uniformly been considered as forming parts or appendages of 

 the labellum, with which indeed their bases cohere. That they 

 are really stigmata, however, I have proved by a careful exa- 

 mination of the tissue of their secreting surface, by the action 

 of the pollen artificially applied to this tissue, by the descent 

 of its tubes, hereafter to be described, along the upper sur- 

 face of the styles which is destitute of epidermis, and by 

 the consequent enlargement of the ovarium. Diplomo-is of 

 Mr. Don*, which may also be regarded as a species of Ha- 

 benaria, is another example of nearly the same kind ; and the 



* Prodr. Flor, Nepal, p. 26. 



description 



