West.— A Contribution to the Study of the Marattiaceae . 383 
In the internodal regions of the adult rhizome of this fern there is 
a single ring of branching and anastomosing bundles, from five to twelve 
in number, surrounding a single commissural strand (PI. XXI, Fig. 3 ; Text- 
figs. 14, B, and 15). The leaf-traces, which consist of several strands, pass 
off as large meshed segments from the dorsal region of the stelar system, 
leaving wide foliar gaps (PI. XXI, Fig. 3; Text-fig. 15). The commissural 
strand ( c.s . in PI. XXI, Fig. 3, and in Text-fig. 15), which in this genus, 
according to Campbell (20, p. 184), arises late in the development of the 
vascular system, pursues a somewhat sinuous course through the central 
Text-FIG. 15. Kaulfussia aesculifolia , Bl. Front view of a model 1 of the stelar system of a 
portion of the rhizome of an old plant, c.s., commissural strand; comp.s., compensating strand; 
leaf-trace; r.t., root-trace (cf. PI. XXI, Fig. 3). 
ground-tissue, and below a leaf-gap gives off either a single strand, which 
immediately dichotomizes, or, more often, two separate strands, which, 
fusing with bundles of the peripheral ring, help to close the foliar gap (PI. XXI, 
Fig. 3, and Text-fig. 15, comp.s). 
A root-trace (PI. XXI, Fig. 3, and Text-fig. 15, r.t.') usually joins the 
commissural strand immediately before the latter gives off a branch (or 
two branches) to close the leaf-gap ; the great majority of the root-traces, 
however, are inserted indiscriminately upon any of the stem-meristeles and 
apparently bear no intimate relation to the number and position of the 
leaf-traces. In the oldest specimens examined, the stelar anatomy had 
1 This model, now in the Botanical Museum of the Imperial College, was prepared by Mr.T. G. Hill. 
