INTRODUCTION. 5 



large and so importaut, that one part must be called, 

 as before, the viscid disc, and the other part the pedicel 

 of the rostellum, to the end of which the pollen-masses 

 are attached. Authors have called that portion of the 

 rostellum which is removed, the " gland " or " retina- 

 culum," from its apparent function of retaining the 

 pollen-masses in their places. The pedicel, or pro- 

 longation of the rostelliun, to which in many exotic 

 species the pollen-masses are attached, seems generally 

 to have been confounded, under the name of caudicle, 

 with the true caudicle of the pollen-masses, though 

 their nature and origin are totally different. The part 

 of the rostellum which is left after the removal of 

 the discs and viscid matter, is sometimes called the 

 " bursicula," or " fovea," or " pouch." But it will be 

 found convenient to avoid all these terms, and to call 

 the whole modified stigma the rostellum — sometimes 

 adding an adjective to define its shape ; that portion 

 of the rostellum which is removed with the pollen- 

 masses being called the viscid disc, together in some 

 oases with the ^pedicel. 



Lastly, the three outer divisions of the flower are 

 called sepals, and form the calyx ; but, instead of being 

 green, as in most common flowers, they are generally 

 coloured, like the three inner divisions or petals of the 

 flower. In almost all the species, one of the petals, 

 which is properly the upper one, is larger than the 

 others and stands on the lower side of the flower, where 

 it oflers a landing-place for insects, having been carried 

 round by the twisting of the ovarium. It is called 

 the lower lip or labellum, and often assumes most 

 singular shapes. It secretes nectar for the sake oi 

 attracting insects, and is often produced into a spur- 

 like nectary. 



