490 MOSSES AND FERNS chap. 



free and often remains within the sperm cell after the escape 

 of the spermatozoids. 



The archegonium in most species of Lycopodium differs a 

 good deal from that of the other Pteridophytes, especially in 

 the large number of neck canal cells that are usually found. 

 The cells of the axial row may be as many as ten in L. annoti- 

 num, and inL. complanatum Miss Lyon (3) found 14-16 cells, 

 which in some cases had two nuclei in each cell, a condition 

 which is also found in L. phlegmaria. L. cernuum, however, 

 according to Treub, has but a single neck canal cell. 



In the remarkably large number of canal cells, as well as 

 in the occasional development of five instead of four outer cell- 

 rows in the neck (Bruchmann (4), p. 34), Lycopodium un- 

 doubtedly resembles more nearly the typical Bryophytes than 

 does any other of the Pteridophytes. 



The Embryo (Treub (2); Bruchmann (4)) 



Treub has traced the development of the embryo in L. 

 phlegmaria through all its stages, and has shown that L. cer- 

 nuum corresponds closely to it, and Goebel's investigations 

 upon L. inundatum show that this species does not differ essen- 

 tially from the others. The first division in the embryo is 

 transverse, and of the two primary cells the one next the arche- 

 gonium remains undivided, or divides once by a transverse 

 wall and forms the suspensor, which is characteristic of all in- 

 vestigated Lycopodineae, while the lower cell alone gives rise 

 to the embryo proper. In the embryonal cell the first wall is 

 a somewhat oblique transverse one, which divides it into un- 

 equal cells. In the larger of these a wall forms at right angles 

 to the primary wall (Fig. 285, A), and this is soon followed 

 in the smaller cell by a similar one, so that the embryo is di- 

 vided into quadrants. Of these the two lower form the foot, 

 while of the upper ones in L. phlegmaria, the one formed from 

 the larger of the two primary cells (moitie convexe of Treub) 

 produces the cotyledon, the other the stem apex. The primary 

 root, which in Lycopodium arises very late, originates from 

 the same quadrant as the cotyledon. 



In L. cernuum, while the early divisions correspond exactly 

 with those of L. phlegmaria, the further development of the 

 embryo shows some noteworthy differences. As in that 



