CHAPTER XXXII. 



LYCOPODIALES. 



The Lycopodiales, or Club Mosses, to which Lycopodium and 

 Selaginella belong, are Vascular Plants of varied land habit. They 

 have relatively small leaves [micro phyllous), borne upon a prepon- 

 derating axis which is usually branched, and is rooted in the soil. 

 The branching of both root and stem is typically dichotomous, but 

 frequently transitions may be seen to moyiopodial branching : that 

 is, where a new branch arises laterally below the apex of the originat- 

 ing part. Many early fossils belonging to this Class, for instance Lepi- 

 dodendron and Sigillaria, were tree-like : others were relatively small, 

 as are all the living Lycopods. More or less definite fertile cones or 

 strobili are borne on the ends of their branches. Somewhat compressed 

 in the axil of each leaf is a single sporangium that opens when ripe 

 like an oyster, by a marginal slit. These characters are common for 

 the Lycopodiales, modern and ancient. 



This Class is represented in the British Flora by some five species 

 of Lycopodium (Fig. 404 a) : they are native on heaths and moors, 

 chiefly in hilly districts. Nearly 100 other species are widely spread 

 through the temperate zones and the tropics. They are mostly 

 low-growing plants, but some are epiphytes. There is in Britain 

 only one native species of Selaginella (S. spinulosa), a minute plant 

 of mossy hill-sides (Fig. 404 b). But over 300 species of the genus arc 

 spread through the tropics. Many species are in cultivation. They 

 are mostly low-growing and shade-loving plants of straggling habit. 

 Another British representative of the Lycopodiales is that curious 

 inhabitant of freshwater lochs, hoetes lacustris, with its long let 

 crowded upon a short succulent stock, which is fixed in the mud 

 at the bottom, by dichotomising roots. These relatively inconspicuous 

 plants are the meagre present-day representatives of the Lyco- 

 podiales, a type of which grew to tree-like size in the Coal Teriod, and 

 b.b. 511 2K 



