346 



GENERAL MORPHOLOGY OF PLANTS 



spirally around it. These uncoil when dry and coil up when 

 wet. This aids the spore's movement. Several are often 

 entangled together and are thus enabled to form a small colony 

 of prothallia when carried away by the wind. 



513. The gamete plant (gametophyte) of Equisetum. 

 When the spores germinate they form two kinds of prothallia: 

 some produce small prothallia with only sperm cases (antheridia) , 

 while others produce larger prothallia with lobes, and egg cases 

 (archegonia) situated near the origin of the lobes. There is thus 

 a dimorphism in the prothallia of Equisetum, and cross fertiliza- 

 tion is enforced. 



THE CLUB MOSSES (CLASS LYCOPODINEvE). 



514. The lycopods, or large club mosses (Lycopodium) . 



These plants are called club mosses be- 

 cause in most species the spore-bearing 

 leaves are grouped into a terminal spike 

 or cone (strobilus), somewhat resembling 

 a club, and because the small, crowded 

 leaves, arranged in spirals on the slender 

 stems, give them the appearance of the 

 leafy stem of a moss. But they are not 

 true mosses, since the leafy stem of the 

 lycopods is a spore plant (sporophyte) 

 while that of the true mosses is a gamete 

 plant (gametophyte). This 

 may help us to understand 

 why the leaves and stems of 

 the mosses and liverworts are 

 not true leaves and stems, 

 since true leaves and stems 

 when present are only formed 

 on the spore plant phase of 



Fig. 330. 



Lycopodium lucidulum, bulbils in axils of 

 leaves near the top, sporangia in axils of leaves 

 below them. At right is a bulbil enlarged. 



plants. The lycopods occur 

 in damp, moist situations, usually in the forest. Some of them 

 have long, creeping stems in addition to the upright stems. 





