LYCOPODINEM 



521 



four-sided one, from which are then produced two similar ones 

 by the formation of a median wall, and a true dichotomy of the 

 primary axis thus takes place at once, the two new branches 

 growing out at right angles to the cotyledon. While this may 

 also occur in 6". Kraussiana (Fig. 301, D), it is not always the 

 case, and frequently the young plant remains unbranched until 

 it has reached a length of a centimetre or more, and has pro- 

 duced numerous leaves. 



Fig. 301. — Selagmella Kraussiana. A, Macrospore with the prothallium (.pr), X50; B, 

 young sporophyte still attached to the spore (sp), X8; cot, cotyledons; R, root; C, 

 upper part of an older stage, X6; D, a still older one showing the first di- 

 chotomy, X4- 



The embryo of S. spinulosa (Bruchmann (4) ) has a short 

 and massive suspensor, and no foot is developed. 



Miss Lyon (2) found that in both S. apus and 5". rupestris, 

 fertilisation occurred while the spores were still within the spo- 

 rangium, and the sporangium attached to the strobilus. "The 

 strobilus of S. rupestris retains its physiological connection 



