THE YOUNG Sl'OROl'HYTE 



147 



and that the secondary veins are pinnately arranged with reference to the midrib. 

 These later veins, however, may show dichotomous branching. I made an examina- 

 tion of a considerable number of young sporophytes collected at the same place where 

 Professor Farmer secured his specimens, but very few of the plants that I collected 

 showed this pinnate venation in the cotyledon, although it is usually conspicuous 



Young sporophyte oi Marattia douglasii still attached 

 to thr gametophyte, pr; Natural si/r. 



Fig. 12^. 



A. Young sporophyte of Kaulfussia attached to 



gametophyte, pr. X2. 



B. Cotyledon from another plant. X2. 

 C A later leaf; si, stipule. Xl. 



in the second leaf. Figure 124, C, shows drawings of a number of the forms from 

 my collection, showing the variation from a strictly pinnate to a perfectly dichoto- 

 mous venation. Many of them show an intermediate venation, but with very few 

 exceptions, even where a midrib was present, this was forked at the apex, indicating 



F10. 124. 



A. Young sporophyte of Angiopttris, with three leaves, i, the cotyledon. Xz. 



B. Young cotvlcdon. X20. 



C. Three cotyledons, showing the variation in form. X3. 



that there had been an early dichotomy. This primary dichotomy of the apex was 

 well shown in a section through a very young leaf (fig. 1 12, B) where there was no 

 question that such a dichotomy was taking place. 



In Dancea there is much the same variation in the form of the cotyledon as in 

 Angiopteris. Brebner's figures of D. simplicifolia show that the cotyledon in this 

 species has a midrib with two lateral veins near the base, but sometimes the midrib 

 forks at the summit, indicating again the early dichotomy of the cotyledon. In one 



