364 THE STORY OF PLANT LIFE 



consist of one to two distinct stamens. The anthers 

 are one- to two-celled, and open transversely. The 

 pollen is spherical. The female flowers consist of 

 one carpel. There are one to six basal, erect, ortho- 

 tropous or anatropous ovules. The ovary is one- 

 celled. The style is short, and the stigma is simple, 

 blunt or funnel-shaped. The micropylar end of the 

 integument forms a lid to the seed. The fruit is 

 bladdery and indehiscent. It is a bottle-shaped 

 utricle. There is one seed or more than one. The 

 testa is thick, and ribbed. The inner coat is thick- 

 ened and discoid above the radicle. The endosperm 

 is fleshy or absent, or slight, and there is an axile 

 embryo, which is cylindrical, stout and straight. 



Ivy-leaved Duckweed (Lenina trisulca). 



There is no apparent reason for the name Lemna, 

 given by Theophrastus, the name being the original 

 Greek name. The second Latin name refers to the 

 trifid character of the frond, which is Ivy-like in 

 form. 



This species is found in the British Isles from cen- 

 tral Scotland, where it is rare, southward, and in 

 Ireland where it is local, and the Channel Islands. 

 It appears to be more widely distributed on the 

 Continent. 



Still waters form the habitat, such as ponds, ditches, 

 or stagnant waters, e. g. canals. The plant is found 



