384 



BOTANY. 



Order Lycopodiaceee. — The prottallinm is known only in one case, 

 viz., Lycopodmm, annotinum-. It was discovered underground by 

 Fankhauser in 1873, who described it* as a yellowish white, irreg- 

 ularly lobed body, sparingly furnished on its under surface with small 

 root-hairs (Fig. 374, A). In its upper surface the prothallium bears 



antheridia, which are 

 deeply sunken in its tis- 

 sue {an. Fig. 274, A); 

 the spermatozoids, which 

 are numerous, are stout 

 and slightly twisted. 

 The archegonia were 

 only seen after the young 

 plants had grown con- 

 siderably (Fig. 274, B) ; 

 they are likewise devel- 

 oped upon the upper 

 surface of the prothal- 

 lium, and appear to bear 

 a considerable resem- 

 blance to those of the 

 Op7uoj!ossacem. 



The young plant which 

 results from the growth 

 of the fertilized germ- 

 cell is quite simple, but 

 it soon takes on the form 

 of the mature plant. 

 The leaves are crowded 

 in Lycopodium, but are 

 less so in tlie other gen- 

 era. In many species 

 the sporangia are borne 

 in the axils of the or- 



Fig. 276 — GiTmination of the spores of Selaginaia. 

 1, longitudinal i^ection of a macrospore of S. Murten- 

 aii; above the line d is the prothallium, below it the 

 " endosperm ;" «, «', two embryos, the laiger one with 

 its suepensor projecting into the nect of the archego- 

 ■ ; left — ' 



nium ; at the 1 

 chegonium ; several root 



of the larger embryo is a young 

 ral root-hairs are also shown. S 



young archegonium of the same species, not yet open 

 3, an archegonium of the same species, with the germ- 

 cell fertilized and divide d into two. A, a microspore 

 of S. caulescens, rendered transparent, showing the di- 

 vision of the contents into the primordial cells ; the 

 small lower cell is the rudimentary prothallium. D, 

 later stage of the same, showing the large antheridium 

 filled with sperm-cells ; t), the rudimentary prothal- 

 lium. All magnified.— After Pfeffer. 



2, a dinary leaves, but in 



others the leaves which 

 bear sporangia are col- 

 lected into cone-like or 

 spike - like structures, 

 which terminate certain 

 branches (Fig. 375). The 

 sporangia are more or less globose bodies, which are short-stalked 

 or sessile ; they contain large numbers of small spores, which escape 

 by an apical slit in the sporangium. 



* J. Fankhauser ; " Ueber deu Vorkeim von Lycopodium," iu Botan- 

 itche Zeitung, 1873, No. 1, 



