The Anatomy of Nephrolepis volubilis J.Sm. 269 
shown (natural size) in Text-fig. 2. It will be seen that the 
direction of coiling does not show any regularity. When young, 
these stolons are comparatively soft and pliable (one such young 
stolon is visible in Text-fig. 1 , y), but the older ones, after coiling 
round supports become wiry on account of the very thick-walled 
cortex. These structures are undoubtedly of great help in support¬ 
ing the primary stolon during its growth upwards among bushes and 
trees. The primary stolon itself may be seen to be loosely twining 
in Text-fig. 1. 
Attention has already been drawn on p. 253 to the extra¬ 
ordinary habit of N. volubilis. The primary stolon makes it 
possible for the lateral plants to reach a very considerable height 
on trees, and though these lateral plants appear to be devoid of 
roots it is possible that these may develop when the plants are 
artificially severed from the stolon on which they are borne. From 
the large number of scars of fallen lateral plants on the primary 
stolon the surmise may perhaps be ventured that the lateral plants 
may be shed from the stolon after they have formed their leaves at 
the expense of the mother-plant. 
Sperlich’s 1 view regarding the origin of epiphytism in 
Nephrolepis is peculiarly borne out by the plant under consideration. 
He regards the possession of stolons by Nephrolepis as having 
probably been the initial stage in the gradual emancipation of the 
plant from the soil. This would be an analogous case to that of 
many phanerogamic epiphytes which according to A. F. W. 
Schimper have evolved from lianes rooted in the soil. The 
occurrence, within the genus, of a facultative epiphyte like 
N. cordifolia may not, perhaps, be quite without significance in 
this relation. 
VI. Theoretical Considerations. 
We may pass now to some of the considerations of theoretical 
interest attaching to the genus Nephrolepis. Of these, the one that 
has aroused the most prominent interest of investigators is 
undoubtedly the morphological nature of the stolons, which was 
responsible for the Lachmann-Trecul controversy, 2 the former 
author holding that they were cauline structures while the latter 
contended that they were roots. This question would seem to have 
1 Flora, 1908, pp. 357-8 and 360. 
* Various papers in the Comptes Rendus, of which only the following need 
be mentioned : Lachmann, vol. Cl, 1885, p. 603 ; Trecul, vol. Cl, 1885, p. 920 ; 
Tr6cul, vol. CVIU, 1889, p. 1081. See also Lachmann, Contributions, etc., 
1889. 
