CuAi. VIII FLOWERS OF ORCHIDS. 241 



of Malaxis paludosa, the close resemblance between the 

 two membranes of the clinandrum and the fertile 

 anther, in shape, texture, and in the height to which 

 the spiral vessels extended, was most striking : it was 

 impossible to doubt that in these two membranes we 

 had two rudimentary anthers. In Evelyna, one of the 

 Epidendrese, the clinandrum was similarly formed, as 

 were the horns of the clinandrum in Masdevallia, which 

 serve in addition to keep the labellum at the proper 

 distance from the column. In Liparis petidula and 

 some other species, these two rudimentary anthers form 

 not only the clinandrum, but likewise wings, which 

 project on each side of the entrance into the stigmatic 

 cavity, and serve as guides for the insertion of the 

 pollen-masses. In Acropera and Stanhopea, as far as 

 I could make out, the membranous borders of the 

 column, down to its base, were also thus formed ; but 

 in other cases, as in Cattleya, the wing-like borders of 

 the column seem to be simple developments of the two 

 pistils. In this latter genus, as well as in Catasetum, 

 these same two rudimentary stamens, judging from the 

 position of the vessels, serve chiefly to strengthen 

 the back of the column ; and the strengthening of the 

 front of the column is the sole function of the third 

 stamen of the inner whorl (ag), in those cases in 

 which it was observed. This third stamen runs up 

 the middle of the column to the lower edge, or lip, 

 of the stigmatic cavity. 



I have said that in the OphreaB and JSTeottese the 

 spiral vessels of the inner whorl, marked a^, a^, a^ in 

 the diagram, are entirely absent, and I looked care- 

 fully for them ; but in nearly all the members of these 

 two tribes, two small papillae, or auricles as they have 

 been often called, stand in exactly the position which 

 the two first of these three anthers would have occupied, 



