190 BRITISH FLOWERING PLANTS chap. 



LuDWIGIA 



L. palustris. — A rare plant, found in boggy pools in 

 Sussex and Hampshire. The minute flowers have no 

 petals. 



CiRC/EA 



In this genus the leaves are opposite, and the parts 

 of the flowers in twos. We have two species — one 

 hairy, C. lutetiana ; and one glabrous, C. alpina. In 

 both the capsule is pear-shaped, and covered with stiflf 

 hooked hairs. The small white honeyed flowers are 

 borne in racemes. The stamens are at first some little 

 distance from the stigma, and at this stage the flower 

 is adapted for cross-fertilisation. In the absence of 

 insect- visits, which are not frequent, the stamen 

 gradually curls over and finally touches the stigma. 



HALOEAGEiE 



Myriophyllum 



We now come to an aquatic genus in which the 

 leaves are, as in so many water plants, divided into long 

 filaments. There are three British species. In one, 

 M. spicatum, the bracts are shorter than the flowers ; 

 in the second, M. verticillatum, they are longer ; while 

 in M. alternijlorum the bracts are longer than the 

 female, but shorter than the male flowers. The species 

 are more or less amphibious, and the water forms differ 

 considerably from specimens growing on land, especially 

 by the shortening of the internodes. 



M. spicatum. — The flowers are in aerial spikes, with 

 small bracts ; the upper flowers are male, the lower 

 female. They are wind-fertilised. 



M. verticillatum. — This species lives in clear deep 

 water, and the flowers are all immersed ; the bracts are 

 pinnate like the leaves. 



