J 5 
Anatomy of the Ophioglossaceae. Ill ’. 
conditions. The following account is in complete accordance with Gwynne- 
Vaughan’s interpretation of the morphology, the correctness of which 
was indeed evident from the corresponding facts since made out in 
Botrychium. 
I obtained two specimens of Helminthostachys , each showing a small 
branch arising from a short piece of a main axis. The development of the 
branches thus appeared to be associated with arrest of the normal growth 
of the main axis. In this respect, as well as in the structure and position of 
the dormant buds, a close parallel with Botrychium can be traced. 
The first branching specimen was a small piece of rhizome that to all 
appearance terminated in its apical bud. When cut into a complete series 
of sections, however, it proved to consist of axes of two orders. The base 
was a fragment of a small rhizome of adult type, including seven leaf-gaps ; 
while borne on this, and arising from the dormant bud in relation to the 
most anterior leaf-gap, was a lateral branch. This had continued the line 
of growth of the arrested main axis. The specimen was thus particularly 
favourable for tracing the relations of the vascular system of the branch 
to that of the main stem in a series of transverse sections. 
The structure of the small rhizome, which bore the branch, may be 
very briefly summarized (cf. Text-fig. 4, and PL II, Photos 23-24). The 
stele had a well-marked pith not limited by an internal endodermis. The 
xylem was mainly outer or centrifugal. In some regions the inner xylem 
was fairly developed, but for the greater part of the length of the fragment 
it was feebly represented by isolated tracheides or groups of tracheides. 
It was as usual best represented towards the upper side of the stele. It 
disappeared internal to the leaf-trace, so that the latter departed with an 
endarch strand of xylem (PI. I, Photo 10). The trace passed rapidly 
through the cortex, dividing without adaxial closure of the xylem. A vesti¬ 
gial bud was present in relation to each leaf. Its general structure was as 
usual, but it may be noted that it was not so far in front of the subtending 
leaf-trace, but was situated over , the leaf-gap before this had closed even 
in the xylem tube (Text-fig. 4, A, B). There was no definite vascular dis¬ 
turbance in relation to the bud. On passing forward, the vestigial bud 
over a leaf-gap is first met with (Text-fig. 4, A), the slit in relation to the 
bud then reaches the surface, and the leaf-gap closes (Text-fig. 4, B, c) before 
the separation of the next leaf-trace from the stelar tube commences. There 
is thus a region intervening between one leaf-gap and the next, in which 
the stele is tubular and undisturbed either by a vestigial bud or a departing 
leaf-trace. The appearance of a vestigial bud standing beside the separating 
trace for the next leaf is not seen. These differences in degree will be 
evident on comparing Text-figs. 2 and 4, and have to be borne in mind in 
considering the relations of the actual branch. 
The departure of the leaf-trace subtending this branch and the vascular 
