384 



BOTANY. 



Order Lycopodiaceee. The prothallium is known only in one case, 

 viz., Lycopodium annotinum. It was discovered underground by 

 Fankhauser in 1872, who described it * as a yellowish white, irreg- 

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

 root-hairs (Fig. 274, 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 

 Ophioglos acece. 



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 



Fig. 276. Germination of the spores of Selayinella. less so in the other gen- 



1, longitudinal section of a macro*pore of S. Morten- __ Q T,, , Hr > /,it,a 



sii; above the line d is the prothallium, below it the era> 



" endosperm ;" e, ', two embryos, the larger one with the sporangia are borne 

 its suspsnsor projecting into the neck of the archego- ,-, 'if +1 



nium ; at the left of the larger embryo is a young ar- J 



chegonium : several root-hairs are also shown. 2, a dinary leaves, but in 

 young archegoniurn of the same species, not yet open. , , ,, 1 i 1 



3, an archegonium of the same species, with the germ- others tne leaves wmcu. 



cell fertilized and divid' d into nvo. A, a microspore bear sporangia are col- 



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



vision of the contents into the primordial cells; the lected into cone-like or 



small lower cell is the rudimentary prothallinm. D. Dri ito litu Qtrnptiirpa 



later stage of the same, showing the'large antheridium B P 1Ke ' re8 ' 



filled with sperm-cells ; v. the rudimentary prothal- which terminate certain 



limn. All magnified.-After Pfeffer. branches (Fig. 275). 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 den Vorkeim von Lycopodium," in Botan- 



ische Zeitung , 1873, No. 1. 



