MORPHOLOGY OF ORCHID FLOWERS. 



29 



firmly attached to a jmrt of the rostelhim (the modified stigma) called 

 by Darwin the viscid disk; this prolongation is now recognised as the 

 true caudicle of the pollinia.* In Cattleya and in some allied genera the 

 pollinia are furnished with a ril)bon-like tail formed of a bundle of 

 light elastic threads, and like the iiolleu masses themselves is included 

 in the anther cell (clinandrium), but is distinct from them. This part 

 of the pollinary apparatus varies in size and form in the difterent 

 genera, being sometimes so much reduced as to make its presence 

 difficult to ascertain, while there are instances where it exceeds in 

 bulk the pollinia themselves. For this 

 organ, which is quite distinct from the 

 true caudicle of the Ophryde.e, Mr. 

 Bentham proposed the name apj^endicida. 

 Different both in origin and substance 

 from the caudide of the Ophryoe.i^ and ^ . ^ 



. Pollinia of CnUhija lahiata. 



the appendicula of the Epidendre^ is a, side ; b, trout view, 



the strap-like organ which sup])orts the pollinia of tJic Vandb.e, and 

 connects them with the removable disk or so-called gland of the 

 rostellum, and is itself connected witli the pollinia by elastic extensible 

 ligaments for which Mr. Darwin has retained the nama caudicle. This 

 strap-like appendage is really a double organ, each pollinium Ijeing 

 })rovidcd with its own appendage, but in most of the genera the two 

 are coherent ; in the section Listrohtachys of Angra^cum and in a few 

 other species they are distinct. This structure also varies much in 

 size and sha]je in the different genera, being very thin and elongated 



Pollinia of VANDEiE. 



(/, viscid disk; lied, pedicel (stipes); p, pollen masses. 



A, of Odontoglossuni graude after partial depression, b, of Brassia maculata. 

 c, of Stanhopea saccata after depression, d, of Sarcanthus terctifolius. 



(From Darwin's Fertilisation of Orcliids.) 



in some of the Phalaenopses and Lycastcs, much reduced or almost 

 absent in Maxillaria and Zygopetalum, short and strong in some of 

 the true Vandas, thickened in Catasetum, etc. In nn)st of the genera 

 in Avhich it is more or less elongated, it assumes various shapes and 

 changes of position after removal from the clinandrium. Darwin called 

 this organ the pedicel of the rostellum,! but as IJentliaui afterwards 



* Sec Fi^. of Ophrijs muscifera, U. 

 t Fertilisation of Orchids, p. 181. 



