FROG-BIT TRIBE J69 



Class II 

 MONOCOTYLEDONOUS PLANTS 



In the plants belonging to this class the embryo of the seed is 

 accompanied by a single cotyledon. The stem consists of woody 

 fibre, cellular tissue, and spiral vessels ; but there is no true bark 

 nor pith, nor is the wood arranged in concentric layers. The stem 

 increases in density (scarcely at all in diameter) by deposits at or 

 near the centre ; hence plants of this class are called Endogenous 

 (increasing by additions on the inside). As new substance is 

 deposited, the old layers of wood are pressed outwards, and thus 

 the hardest part is near the circumference. The growth of the 

 stem is usually produced by a single terminal bud, without the aid 

 of buds in the axils of the leaves ; there are, however, exceptions 

 to this rule, and the stem is often hollow. The principal veins of 

 the leaves are parallel, not forming a complicated network. The 

 flowers are furnished with stamens and pistils, 3, or some multiple 

 of 3, being the predominating number of the parts of fructification. 

 A large number are destitute of petals, the place of which is supplied 

 by scales or chaff (glumes). 



Sub-Class I 

 PETALOIDE^ 



Flowers furnished with petals, arranged in a circular order, or 

 without petals.* 



Natural Order LXXIX 

 HYDROCHARIDACEjE. Frog-bit Tribe 



Flower-buds enclosed in a sheath ; sepals 3, green ; petals 3 ; 

 stamens 3, 9, 12, or more ; ovary inferior, 1 or many-celled ; style 1 ; 

 stigmas 3-9 ; fruit dry or juicy, not bursting, 1 or many-celled. 

 A tribe of aquatic plants, often floating, among which the most 

 remarkable is Valisneria spiralis, the flower of which grows at the 

 extremity of a long, spiral stalk. As the bud expands the spire 

 partially uncoils, allowing the flower to float on the surface for a 

 few hours, and then contract again, drawing the seed-vessel beneath 

 the surface, there to ripen its seeds. The number of species is 



* Sub - Class II, Glumace^, contains plants which have, instead ol 

 petals, chaffy scales, or glumes, which are not arranged in a circular order, 

 as is the case with Petaloidca, but are imbricated, such as the Grasses 

 or Sedges. 



