THE CLUB MOSSES. 119 



The Club Mosses (Lycopodium). 



The Club-mosses, though associated with the Ferns on 

 account of the similarity of their reproductive processes, and by 

 reason of certain structural affinities, present no resemblance of 

 form. Popularly, they are regarded as merely a larger kind of 

 Moss and distinguished by the name of Stag-horn-moss ; and 

 certainly on a mere superficial view they must appear to have 

 closer kindred with the Mosses than with the Ferns. 



They have long tough wiry stems which creep along among 

 moss and grass and stones, attaching themselves by sending 

 down at intervals white wire-like roots straight into the soil. 

 The stems multiply by forking into pairs, and they are densely 

 clothed by overlapping leaves which are always simple in form 

 that is, though they may have toothed edges they are never 

 divided like the fronds of most ferns. 



The spores are contained in small, leathery, two-valved cap- 

 sules which, instead of being clustered in sori as in the true Ferns, 

 or on the backs of scales of a terminal cone as in the Horsetails, 

 are produced on the upper surface of the leaves at their base 

 (Plate 130). In some species a specialized terminal or side 

 shoot has the leaves modified into scales, and the kidney-shaped 

 capsules will be found in the axils of these. The roundish 

 spores are marked with three radiating lines, and it is along 

 these lines, when germination begins, that the outer cuticle 

 splits to allow the exit of a filament which develops into the 

 prothallium. Both antherids and archegones are produced on 

 the same prothallium. In some species (e.g. L. annotinuni) 

 the prothallium is an underground tuberous mass of a pale 

 colour without any green coloring matter. The details of the 

 early developmental processes in the Club-mosses have not 

 been observed as yet with the fulness that characterizes our 

 knowledge of the corresponding stages in the Ferns ; but there 

 is reason to believe that they follow a similar course. 



