12 Tansley and Lulham. 
are continuous with the inner strands of the main stem, as may be 
seen in Figs. 14—25 (which represent a series of transverse 
sections of the rhizome passing through the node, the transverse 
section of the base of the petiole, in a plane at right angles to the 
parallel planes of the series, being also shewn in Figs. 18—24). while 
Figs. 26 — 34 . 
Figs. 26—34. Pteris aquilina. Selected sections from a transverse series 
through the base of the petiole including the origin of a lateral 
(posterior) bud (see Fig. 13). Lateral folds of petiolar system (A. 11 ,— 
above bud A 1 , B) and inner vascular ring of bud, black ; dorsal (adaxial) 
and ventral (abaxial) strands, white : sclerencliyma diagonally lined. 
the strands left white are those derived from the outer circle of the 
rhizome. From an inspection of these series it is quite clear that 
the strands forming the lateral bays (A, B, A 1 , B 1 ,) of the petiolar 
system are continuous with the inner strands of the rhizome, while 
the whole of the abaxial curve together with the free margins of 
the petiolar system are continuous with the outer strands of the 
rhizome. Thuswhilein Pteris incisa var. integrifolia thecontinuations 
backwards of the lateral bays of the leaf-trace gradually die out in 
the rhizome, in Pteris aquilina they form an inner system of 
rhizomic vascular strands continuous throughout the internodes, for 
