254 BOTANICAL GAZETTE [march 



the traces for the older leaf (i') are supplied from the cauline strands 

 numbered 2, 7, 14, 17, and 20. The strands from 2 and 20 will 

 girdle the stem cylinder, those from 7 and 17 will make a p3,rtial 

 girdle, and that from 14 will enter the leaf petiole directly. Fig. 15 

 is an attempt at demonstrating the same condition lower down in 

 the stem. For the purpose of making the condition clearer the 

 vertical magnification was made greater than the horizontal one. 



Many angiosperms which have both "radical" and cauline 

 leaves give illustration of this same condition. In the second year 

 stems of such plants each node is located at some distance above 

 the older one, and the leaf traces arising on the side of the stem 

 opposite the leaf describe a spiral or obhque arc before entering the 

 leaf. In the part of the stem from which the so-called "radical" 

 leaves spring, however, the vascular strands destined for these 

 leaves describe a horizontal arc similar to the leaf trace girdle in all 

 parts of the cycad stem. 



A careful but vain search was made for cortical cambium, 

 vestigial traces of the primitive polystele of the Cycadofilicales. 



Germination 



Germination is hypogean, like that of all other members of the 

 order thus far described. When the embryo has grown to the full 

 length of the seed, the thin portion of the stony coat surrounding 

 the micropyle yields to the pressure exerted upon it by the base of 

 the axis. This base, scarcely more than a root sheath, emerges, 

 pushing before it the brown and withered remains of the suspensor 

 and archegonial wall. The cotyledonary base elongates and bends 

 downward, and the root tip' emerges from its sheath (fig. 3). If 

 the embryo is a monocotyledonous one, that is, if its whole coty- 

 ledonary apparatus is a single sheath surrounding the plumule, this 

 sheath is split by the radial growth of the axis; if there are two or 

 more distinct cotyledons, their petioles are separated by the same 

 cause (fig. 4). The plumule then emerges from the seed and be- 

 comes erect. Of course, when the seeds germinate while in a 

 vertical position, the root and the plumule develop in the same 

 axis (figs. 5, 6). In 3 of the seeds double embryos developed 

 (fig- 29). 



