476 MOSSES AND FERNS chap, xiy 



branches, and formed without any relation to the leaves. 

 Before the bulblet becomes detached, the rudiment of a root 

 can be made out at the base, and as soon as it falls off and 

 comes in contact with the earth the root begins to grow and 

 fastens the bulblet to the ground (Fig. 248, C). The axis of 

 the bulblet, which at first is very short, rapidly elongates, and 

 the leaves formed up it have the characters of the ordinary 

 ones. As the leafy axis develops the fleshy leaves of the 

 bulblet lose their chlorophyll completely and finally decay. 



Hegelmaier ^ describes mucilage ducts in the stem and 

 leaves of L. inundatitm and some other species, which are not 

 unlike those found in Angiopteris. 



The Sporangia 



The most recent and accurate account of the structure and 

 development of the sporangia of the Lycopodineae is that given 

 by Professor Bower in his recent memoir upon this subject.^ 

 His investigations include a number of species of Lycopodmm, 

 and the following account is taken mainly from his memoir. 

 The results of his investigations show that there is much more 

 variety shown than was before supposed, both in the form of 

 the sporangium itself and in the mode of origin and number of 

 the archesporial cells. 



In L. selago the sporangium originates upon the upper 

 surface of the sporophyll close to its base, and in radial section 

 the young sporangium appears to originate from a single cell ; 

 but this is really only one of a transverse row of cells, all of 

 which participate in its formation. Each cell of this primary 

 row divides first into a large central cell (Fig. 249, C, x) and 

 (in radial section) two peripheral ones. The central cell next 

 by successive periclinals forms a row of three cells, of which the 

 middle one is the archesporium, which, judging only from radial 

 sections, seems to consist only of a single cell ; but comparing 

 with the radial section a tangential one, it is seen that the 

 archesporium really consists of a row of similar cells (Fig. 249, 

 F). The growth in the upper part of the sporangium is 

 stronger than below, so that a distinct, although short stalk is 

 formed. The archesporial cells rapidly divide, but show little 



^ Plegelmaier (i). 

 - Bower (15) ; also Goebel (3), Bot. Zeit. 18S0, p. 561 ; Sadebeck (6), p. 313. 



