THE OLDER SPOROPHYTE 



183 



hairs, which resemble those in Dancea in being multicellular. In the larger roots 

 there may sometimes be five or six cells, each with a conspicuous nucleus, making 

 up these root hairs, and sometimes they show signs of branching at the apex. 



It is evident that in Kaulfussia, up to the time that five leaves have developed, 

 the vascular system of the stem consists of a single axial strand, a sort of sym podium 

 formed by the completely united traces of the young leaves. The xylem may appear 

 as a single mass at the points where fusion of the leaf traces is complete, but at most 

 points the individuality of the component strands is maintained, so far as the xylem 

 is concerned. 



Figure 168 shows transverse sections from a much older sporophyte. The 

 section of the petiole still shows the single vascular bundle having near its inner face 

 a single large mucilage duct, which follows the leaf trace downward into the stem. 

 As the bundle from the leaf enters the stem it broadens, and there is a separation 

 of the xylems into two masses, first seen in the fourth leaf. In the specimen shown 

 here the earliest leaves were not sectioned, and, as it can not be stated exactly how 

 many leaves the young sporophyte had developed, it must therefore remain uncer- 

 tain which leaf first shows the completely divided leaf trace. In the specimen in 

 question the oldest leaf that showed had a single trace with two separate xylems, 



Fig. 167. — Three longitudinal sections of an older sporophyte of Kaulfusiia. X25. 



while the next leaf had the leaf trace completely separated and resembling a corre- 

 sponding stage in Dancea (fig. 168, /"). As the traces from the two leaves approach 

 preliminary to their fusion, the double leaf trace has its parts united again so that 

 the traces become single before they join. The leaf trace now forms a single bundle, 

 crescentic in section and very much like the single broad leaf trace from the earlier 

 leaf. The two traces come nearer and nearer and finally fuse on one side, so that 

 a section shows a single bundle almost circular in form, but broken on one side 

 (fig. 168, H). This break is finally closed up, and the section of the bundle is 

 completely circular and resembles very closely that of Botrychium or Helminthos- 

 tachys, except that phloem is developed inside the ring of xylem (fig. 1 68, K). A 

 similar condition may sometimes be found for a very short time in the young plant 

 of Datura also. 



No certain evidence of an internal endodermis could be made out and tin- 

 external endodermis is also somewhat vague, although there is probably no question 

 of its presence. The outer phloem is bounded by a fairly well-defined pericycie, 

 between which and the starch-filled cortical cells of the stem are two or three layers 

 of transparent cells, some of which presumably constitute the endodermis. The 

 endodermis is certainly present in the free leaf tracts, although less conspicuous 



