THE DICOTYLEDONES 



1909 



Fig. 1829. — Lathraea squainaria. Inflores- 

 cences. 



flowers for nectar secreted near the base of the ovary. If cross-polUnation 

 fails, the anthers may be carried outside the flowers by the elongation of 



Fig. 1830. — Lathraea sqinuiiarid. Longitudi- 

 nal section of flower to illustrate pollina- 

 tion. See in text. 



their filaments, when wind-pollination of the upper flowers of the 

 inflorescence is made possible. 



Lathraea clandestina (Fig. 183 1), with large purple flowers, is parasitic 

 on Willow and allied shrubs. It is occasionafly cultivated in shrubberies. 

 The fruit is a capsule which opens explosively. 



The genus Orobanche (Broomrape) contains about 100 species which are 

 parasites found in temperate and subtropical regions. Several occur in 

 Britain. Some parasitize only a single host plant, for example O. elatior 

 occurs on Centaurea and O. hederae on Ivy. Others, like O. apiciilata, are 

 less restricted in the plants they parasitize. 



