23 



(caudicle), whicn sometimes terminates in a small flat circular 

 plate, termed the viscid disc, near a small projection in the front 

 of the column and the base of the anther-cell termed the rostellum, 

 or little beak. All these parts are well shown in Fig. 6., repre- 

 senting a section of a Cattleya column. To this normal arrange- 

 ment there is a curious exception in the genus Cypripedium, 

 where the part usually occupied by the anther case is transformed 

 into a shield-like plate, the staminode (see Fig. i), and the true 

 anthers, of which there are two, one on each side of this, and 



FIG. 7. 



Side view of Orchis mascula flower, with all the petals and sepals cut ofFexcep' 

 the labellum, of which the near half is cut away, as well as the uppei 

 portion of the near side of the nectary, a, anther, consisting of two cells , 

 r t rostellum ; s, stigma ; /, labellum ; n, nectary. 



partly covered by it, the stigma being beneath the staminode. In 

 some orchids the pollinia is in wax-like masses, as already noted. 

 .In others it is powdery, but this character is employed in the 

 classification to be referred to later on. In the production of 

 waxy masses of pollen the orchids are not alone, for the milk- 

 weeds (Asclepias) have their pollen in very similar form. The 

 general structure of the column and position of the parts will be 

 readily understood from an inspection of the two sections (figs. 

 6-7) from Mr. Darwin's " Fertilisation of Orchids," which Mr. John 



