XIII 



LYCOPODINE^E 



525 



velop in the late* summer and autumn, producing at tliis time 

 only macrosporangia. In the spring the growth of the strcj- 

 bilus is resumed, and microsporangia are develo[)e(l, the game- 

 tophytes produced from the macros])ores of th.c previous year 

 being fertilised by spermatozoids developed from the micro- 

 spores developed in the spring. In ^, aptis there was evidence 

 that the embryos formed in the autumn passed tlirough the 

 winter within the macrospore, completing their development in 

 the spring. 



The leaves arise much in the same way that tlie branches 

 do, but do not develop a single apical cell. The growth is 



Fig. 304.— Cross-section of a fully-developed stem of S". Kraussiana, showing the two 

 vascular bundles suspended in the large central lacuna by means of the trabeculae 

 (0, X75; B, a single vascular bundle, X450; x, x, scalariform tracheids; s^ s, 

 sieve-tubes. 



much the same as in the first leaves of the embryo, and as in 

 these the early growth is due mainly to a row^ of marginal 

 initial cells from which segments are cut off alternately above 

 and below. 



