90 



midrib where arcliegonia were Ijorue, was almost entirely free 

 from rhizoids. Rauvvenhofi' examined the archegonia of several 

 species of Gleiche.nla and notes that the neck is straight, but 

 he makes no mention of the presence of the Ijasal cell, nor did 

 he make a detailed study of the canal-cells. In general the four 

 species under consideration here were very much alike, Init 

 there were some minor points of difference. G. peciinat<i proved 

 to be the best for study and this species was carefully examined 

 for the details of development. 



The archegonia (PL XII, Figs. 94—101) are produced in large 

 numbers and are formed in rapid succession near the apex. Cross 

 sections of young archegonia show an arrangement of the cells not 

 unlike that found in Antlwceivs (PI. XII, Fig. 95). The mother-cell 

 of the archegonium is deeper in Gleichenia than is usual in the 

 ferns, this being especially noticeable where the young arche- 

 gonia are crowded. The young archegonium shows at this stage 

 the usual three superimposed cells of which the i)asal one is 

 unusually conspicuous (PL XII, Figs. 96 — 97). The basal cell often 

 undergoes a transverse division while the archegonium is still 

 young, and these cells divide further as the archegonium develops. 

 The first division of the central and outer cells follow the 

 usual course. The outer cell divides ])y intersecting walls into 

 the four primary neck-cells, which divide repeatedly b}^ trans- 

 verse walls until the neck becomes very long. In G. pectutiitu 

 the neck is often nearly straight or is slightly inclined forward. 

 In the latter case the two posterior rows of cells are somewhat 

 longer than the forward ones. The number of cells in each row 

 is about eight to ten. The central cell is, as usual, pushed up 

 between the neck-cells and becomes very much elongated before 

 the primary neck-canal-cell is cut off from it. The ventral 

 canal-cell is then separated from the egg-cell and the neck- 

 canal-cell divides into two (PL XII, Figs. 98—100). In all of the 

 species examined except G. poly pod lolde.'^ there was usually a 

 distinct wall between the canal-cells, such as occasionally occurs 

 in <>snniii<l(i, but which is commonly al)sent in the other lepto- 

 sporaugiate ferns. Less often the division of the nucleus is not 



