242 HOMOLOGIES OF THE Chap. VIIL 



had they been developed. Not only do they stand in 

 this position, but the column in some cases, as in 

 Cephalanthera, has on each side a prominent ridge, 

 running from them to the bases or mid-ribs of the two 

 upper petals ; that is, in the proper position of the 

 filaments of these two stamens. It is, again, impossible 

 to' doubt that the two membranes of the clinandrum 

 in Malaxis are formed by these two anthers in a 

 rudimentary and modified condition. Now, from the 

 perfect clinandrum of Malaxis, through that of Spi- 

 ranthes, Goodyera, Epipactis latifolia, and E. palustris 

 (see fig. 16, p. 101, and fig. 15, p. 94), to the minute 

 and slightly flattened auricles in the genus Orchis, a 

 perfect gradation can be traced. Hence I conclude that 

 these auricles are doubly rudimentary ; that is they 

 are rudiments of the membranous sides of the clinan- 

 drum, these membranes themselves being rudiments of 

 the two anthers so often referred to. The absence of 

 spiral vessels running to the auricles is by no means 

 sufiScient to overthrow the views here advocated as to 

 the much disputed nature of these structures; that 

 such vessels may quite disappear, we have proof in 

 Cephalanthera grandiflora, in which the rostellum and 

 its vessels are completely aborted. 



Finally, then, with respect to the six stamens which 

 ought to be represented in every Orchid: the three 

 belonging to the outer whorl are, always present, the 

 upper one being fertile (except in Cypripedium), and 

 the two lower ones invariably petaloid and forming 

 part of the labellum. The three stamens of the inner 

 whorl are less plainly developed, especially the lower 

 one, Oj, which, when it can be detected, serves only to 

 strengthen the column, and, in some rare cases, accord- 

 ing to Brown, forms a separate projection or filament ; 

 the two upper anthers of this inner whorl are fertile 



