72 GERANIACE^E. [chap. 



GERANIACEaS. 



This order contains four British genera ; Geranium, 

 Erodium, Oxalis, and Impatiens. 



The genus Geranium possesses a peculiar interest 

 in the history of the present subject, because, as 

 Sprengel tells us, the hairs in the corolla of G. 

 sylvaticiim (See p. i), attracted his attention, and led 

 to the researches which are so well described in his 

 interesting work. 



The flowers of the species of Geranium differ con- 

 siderably in size : the larger flowered species, such as 

 G. sanguineum, G.pkceum, G. pratense (^\gs. 40 and 42), 

 and G. sylvaticum, being perennial, the smaller ones 

 annual, or biennial. Geranium palusire, with which G. 

 tratense, G. sylvaticum, and G. sanguineum, closely 

 agree, is taken by Sprengel as a type of the large 

 flowered species. The honey glands are five in number, 

 situated near the base and at the outer side of the 

 outer stamens ; and are efiectually protected by 

 fringes of hairs arranged just above them, so as to 

 prevent any rain from obtaining access to them. 



The stamens are ten in number, of which one half 

 are longer than the remainder ; the pistil terminates 

 in five lobes, the upper surfaces of which constitute 

 the stigmas. The flower opens widely by day, hangs 

 down, on the contrary, and partially closes at night. 

 The petals are ornamented by purple lines, which 

 serve as honey-guides, pointing to the honey glands. 

 When the flower first opens (Fig. 41) the stigma is 

 immature, and the five lobes are closely pressed 



