54 



VASCULAR CRYPTOGAMS 



the young prothallium now consists of an axial row of four short ceUs, 

 the basal and apical cells, and two lateral rows. The cells contain a 

 few grains of chlorophyll. The formation of the sexual organs was not 

 observed. The mature oophyte of L. annotinum (L.) presents several 

 important differences. The prothallium is underground and of a 

 yellowish-white colour, destitute of chlorophyll, and consists of a tuberous 

 mass with cushion-like ridges on the upper side and a few small rhizoids. 

 On its upper side and completely imbedded in the tissue are a number 

 of antherids, consisting of cavities covered by one or more layers of cells, 



and containing a large number of mother-cells 

 of antherozoids. The antherozoids themselves 

 appear to be minute bodies consisting of only 

 a few coils, and probably with two cilia. The 

 archegones have not been actually observed, 

 but are evidently borne on the same prothallium 



A 



B 



i^<mm 



\  \ 



Fig. 35. — A, prothallium o{ Lycopodiian cernman 

 L. ; t, tuberous outgrowth ( x 25). B, young plant 

 of Z. cermium ( x 2). (After Treub.) 



Fig. 34. — Young plant of Lycopo- 

 diiiin annotifihm L. p, prothal- 

 lium; w, root (natural size). 

 (After Fankhauser.) 



as the antherids, and in close contiguity with them, apparently on the 

 upper side, in the depressions between the ridges. Only one archegone 

 appears to be fertilised on each prothallium. The young sporophyte 

 has no foot, its place being supplied by a tuberous swelling with root- 

 hairs. A very different type of prothallium is presented, according to 

 Treub, by L. cernuum (L.). It consists of a short cylindrical axis half 

 immersed in the soil, containing chlorophyll in its exposed portion, and 

 putting out rhizoids from its lower end. The upper extremity bears a tuft 



