286 



MORPHOLOGY. 



buds which contain rudimentary shoot an<l root and several thick green leaves. 

 When they fall to the grounil lliey j^^now into new lycopodiuni plants, just as 

 the bulbils of C}-sto[)teris do \\hich were described in the chapter on ferns. 



583. Note. — The prothallia of the species of lycopodium which have been 

 studied are singular objects. In L. cernuuni a cylindrical body sunk in the 

 earth is formed, and fruni the Uj'per suriace there are gr<*en lolies. In L. 

 phlegmaria and some others slender branched, colorless bodies are formed 

 which according to Treub grow as a saphrophyte in decayed bark of trees. 

 Many of the prothallia examined have a fungus growing in their tissue wdiich 

 is supposed to play some part in the nutrition of the prothallium. 



The little club mosses (selaginella). 



584. Closely related to the club mosses are the selaginellas. 

 These plants resemble closely the general habit of the club mosses, 

 but are generally smaller and the leaves more delicate. Some 

 species are grown in conservatories for ornament, the leaves of 



Fig. 3j8. Fitr. 320. Fis. 330. Fin. 33T. 



Selaginella w i t h Fruiting s p i tc e Large spo- Small spo- 



three truiting spikes, sliuwing large and rangiiiiii. rangiinn. 



(Selaginella apus.) small sporangia. 



such usually having a beautiful metallic lustre. The lea\'es of some 

 are arranged as in lycopodiuni, but man\- s])ecies ha\ e the leaves 

 in four to si.K rows. Fig. 32S represents a ])art of a selaginella 

 plant (S. apus). The fruiting spike possesses similar lea\'es, but 

 they are shorter, and their arrangement gi\ es to the spike a four- 

 sided appearance. 



