6 
Tansley and Lnlham . 
approached. First an internal fold of the solenostele having the 
form of a closed cylinder, arises on the left side (Fig. 6,a), and 
shortly afterwards a similar one arises to the right of the mid- 
ventral line (Fig. 7 ,b) and shifts up till it occupies a lateral position 
opposite the first. At the same time both of these internal cylinders 
Figs i. — 12 . 
Fig. 4(x6). Pteris rucisa, type, a, solenostele ot internode. b, soleno¬ 
stele broken for departure of leaf-trace, l.t. c, base of petiolar strand 
(of another leaf) in transverse section giving off tlie stele (st.J of a 
lateral shoot. P'rom Gwynne-Vaughail's preparations. 
Figs. 5—12 (x 6). Pteris incisa var. integrifolia. Selected sections from a 
series through the node. Vascular tissue of the two lateral internal 
olds (A, B) and the tissue continuous with them above, black. A 1 , B’, 
lateral folds of petiolar strand. St. Br. t , stele of first branch of the 
dichotomy. St. Br . 2 stele of second branch of ditto, a, z, e, see text. 
