THE 
HEW PHYTOIiOGIST. 
Vol. 3, No. i. January 27TH, 1904. 
THE VASCULAR SYSTEM OF THE RHIZOME AND 
LEAF-TRACE OF PTERIS AQUILINA, L., AND PTERIS 
INCISA, THUNB., VAR. INTEGRIFOLIA , BEDDOME. 
BY 
A. G. Tansley, M.A., 
AND 
R. B. Lulham, B.Sc. 
[Text Figs. 1-59.] 
A S might be expected in the case of so widespread and abundant 
a plant, the structure of the vascular system in the common 
bracken fern has been frequently described and alluded to by plant- 
anatomists. Nevertheless, although it has long been known that both 
the inner and the outer rings of rhizome strands contribute to the 
formation of the leaf-trace, yet the exact course of the leaf-trace 
strands has apparently never been correctly described in adequate 
detail, nor has any attempt been made to bring the whole structure 
into its proper place in the modern theory of Filicinean vascular 
morphology. It is with the object of attempting to fill this gap 
that the present paper has been written. 
Historical. 
The earliest description we can find is that given by Hofmeister 
(’57) who made a fairly thorough investigation of the morphology' 
and development of this plant. He describes how the single cen¬ 
tral vascular strand of the stem of the young plant at the insertion 
of the first leaf has a deep infolding on one side (Taf. II., Fig. 6) y 
while after a number of leaves have been developed and the young 
stem has forked this bay becomes larger (Taf. II., Fig. 7) and soon 
the original strand is separated into two parallel band-shaped 
bundles (Fig. 8), which may branch, the branches again running 
into the main bundle. So far, Hofmeister is confirmed by Leclerc 
