400 



BRITISH FLOWERING PLANTS 



CHA?. 



or rarely 2. There are also normally 3 stigmas, the 

 upper and central one of which is modified into a re- 

 markable organ known as the rostellum (Figs. 328, 331). 

 The anther and stigmas are borne in close proximity 

 on a prolongation of the floral axis known as the 

 column. The stigma is sticky. The pollen is generally 



Upper or posterior sepal. 



Upper 

 petal. 



Labellum, 



Fig. 328. — Section of the flower of an Orchid. SS, stigmas ; Sr, stigma modified 

 into the rostellnm ; A^, fertile anther of the onter whorl ; A^, A^, anthers of 

 the same whorl sometimes present in the form of barren outgrowths (stamin- 

 odes) of the column (as in Orchis), but generally absent ; a^, Oj, rudimentary 

 anthers of the inner whorl fertile in Cypripedium, generally forming staminodial 

 outgrowths of the column ; 1^3, third anther of the same whorl, normally sup- 

 pressed, but occasionally present in abnormal ilowers. 



united by elastic threads, and forms one or two oblong 

 or globular pollen masses. The flowers as a rule pro- 

 duce nectar, often contained in a spur.^ In some cases 

 (Orchis) the nectar does not transude, but the tissue 

 must be bored to obtain the sweet juice. The flowers 

 are very long-lived. Those of our wild orchids are said 

 to retain their beauty often for a month, and some 

 foreign ones for twice or even nearly three times as 



^ In one species, Angroecum sesquipedale, of Madagascar, the spur reaches a 

 length of 18 inches. 



