278 THE STORY OF PLANT LIFE 



In the Hydrocharitacese the flowers are regular and 

 unisexual, in the Orchidacese they are irregular and 

 hermaphrodite. There are but one or two stamens 

 in the Orchid group, three or more in the Frogbit 

 group. In the latter the fruit is a berry, in the former 

 it is a capsule. The Frogbit group is aquatic in 

 habit. The Orchids include many xerophytes and 

 epiphytes. 



75. The Frogbit Group. 



Of the Order Hydrocharitaceae there are some fifty- 

 five species, and thirteen genera. Amongst British 

 types there is the Frogbit, Water Soldier, and 

 Canadian Waterweed, each of which is described. 



They are Tropical and Temperate in range. The 

 British types are fresh-water aquatic plants. Some 

 foreign types are marine. 



Being adapted to aquatic conditions, all are her- 

 baceous, and the leaves are floating or submerged, 

 sometimes ribbon-like. In the Water Soldier the 

 leaves are aerial and partly above water, half-sub- 

 merged. The buds are several in each leaf-axil. 

 The leaves are opposite or in whorls, convolute in 

 bud, entire. 



The plants are dioecious or trioecious. The sexes 

 may be in different flowers, and generally on different 

 plants. The flowers are in the axils, one-flowered in 

 the females, more numerous in the male flowers. 



They are, when young, enclosed in one or more 

 (one to three) bracts, forming a spathe. They are 



