438 PTERIDOPHYTES (FERN PLANTS) 



lively. The gametophy tes are flat, green, branched bodies and lie 

 flat on the substratum. They are of two kinds, male and female. 

 The female gametophyte is the larger and bears the archegonia 

 at the base of thickened lobes. The male gametophyte usually 



Fig. 391. — The gametophytes of Equisetum arvense. A, female gameto- 

 phyte, showing one archegoniimi (or) (X about 20). B, male gametophyte 

 with four antheridia shown ( J ) (X about 40). 



develops the antheridia at the ends of small lateral branches. 

 The gametophytes apparently may be either male or female, the 

 matter of sex depending upon nourishment, the poorly nourished 

 ones becoming males and the well nourished ones females. 



The sperms are multicihate. After the sperms are mature, 

 the walls of the antheridia rupture, thus permitting the sperms to 

 escape and swim to the archegonia. By passing down the hollow 

 necks of the archegonia the sperms reach the eggs. A fertilized 

 egg develops a new sporophyte and thus completes the life cycle. 



Lycopodiales (Club Mosses) 



About one-eighth of the Uving Pteridophytes are Club Mosses. 

 They are commonly divided into four groups — Lycopodium 

 Phylloglossum, Selaginella, and Isoetes — but a study of the 

 Lycopodiums and the Selaginellas will serve to give a general 

 notion of the Club Mosses. 



The Club Mosses, although not Mosses at all, get their name 

 from their Moss-like stem and their club-shaped appearance due 

 to the large terminal strobili which some have. 



Lycopodium. — There are about five hundred species of Lyco- 

 podiums, and they are widely distributed, occurring in all parts 

 of the world and all climates. They grow mostly in moist, shady 

 places and some grow in the water. 



