The Anatomy of Nephrolepis volubilis J.Sin. 267 
It may be instructive to study the behaviour of the vascular 
strands at the origin of such leaves borne directly on the stolons, 
and to ascertain whether such a stolon agrees with the normal 
stolon in internal structure. 
A few remarks on the stolons of some Nephrolepis plants which 
I had the opportunity of observing at the Cambridge Botanic 
Garden may now be made. The plants were all in the same house 
(Tropical Fern House). 
(1) N. Whitmanni. —In a wire cage hanging vertically down 
about 8 feet from the ground. The primary stolons, 1^-2 feet long, 
were all seen growing directly downwards. They bore no roots, 
unlike the stolons of all the specimens that were not in hanging 
pots ; and were less frequently branched than usual. 
(2) N. Whitmanni, N. davallioides (Sw.) Kze., and N. 
todeaoides. 1 —One specimen of each in a pot placed on a table 
covered with moist pebbles. In each case most of the stolons 
arising from the stock on different radii, on reaching the edge of 
the pot, passed close over the edge and then grew obliquely out¬ 
wards and downwards towards the table at an average angle of 
about 45° to the table, the tips in each case being above the level 
of the table. 2 They bore secondary stolons usually only on their 
lower sides, and these grew vertically downwards, never, however, 
touching the table. 
(3) N. cordifolia. —A large specimen bore over 35 stolons, 34 
of which, after passing over the edge of the pot, grew vertically 
downwards, the single exception growing obliquely outwards and 
downwards at about 45°. Several of the vertical stolons, on reach¬ 
ing the moist table passed underneath the pot. 
(4) In an unnamed specimen growing in a pot, the stolons 
were mostly growing downwards but adhering to the outside of the 
pot. 
No definite solution could be arrived at regarding the varying 
behaviour of the stolons in the above four cases. Number I might 
suggest positive geotropism but the stolons, especially when long, 
would hang down merely by their weight. Number 3 is a partly 
similar case, but the passing of the stolons under the pot suggests 
positive hydrotropism, which is also suggested by Number 4. 
Although it did not appear likely that these directions of 
growth were due to mere chance, (because of the considerable 
1 This is probably a garden variety. 
’ This appearance was afterwards seen illustrated (in fig. 90, p. 477 in 
Gard. Chron. I, 1887) for N. rufescens var. 
