262 
Birbal Sahni. 
plant, the parenchymatous xylem has “ three prominences, one 
median and two lateral, where the first formed tracheids occur,” 1 
while between these are bays where the phloem is thickest. It is 
interesting to find near the tip of the leaf of a Polypodiaceous fern 
a stage recalling the primitive condition of Lygodium. The almost 
identical plan of structure, as seen in a transverse section, of a 
Lygodium stem and the stolon of Nephrolepis volubilis has already 
been referred to (p. 254). 
Nephrolepis leaves are well-known to bear chalk-glands on the 
upper surface of the pinnae. These have been described by Poirault 2 
in species of Poly podium, and very similar ones were found in 
N. volubilis. The photograph (Fig. 4) on PI. 4 is intended to show 
the “ spoon ” shape in vertical longitudinal section, mentioned by 
Poirault. The large, round or oval black bodies are apparently 
resinous, but some of them are the prominently staining large 
nuclei of the parenchymatous cells between the swollen reticulate 
tracheids. A couple of spiral and annular tracheids are seen in 
the vein coming up to the gland. 
IV. Other Species of the Genus. 
Having reviewed the anatomy of N. volubilis we may pass on 
to the consideration of a few of the other species which were 
examined. 
(1) N. cordi/olia. Sperlich’s 3 excellent account of the stolons 
of this plant leaves little to be said. From the base of the numerous 
roots on the stolon a longitudinal groove extends towards the apex 
of the stolon, sometimes for a considerable distance, so that a 
cross-section through this region is not quite circular. Each 
groove always overlies one of the four protoxylem strands of the 
stolon, the roots arising in four orthostichies. 
The mode of branching of the primary stolon shows no 
important difference from that in N. volubilis. On account of the 
small size of the stele, it is not possible to dissect it out neatly 
enough to show the behaviour of the protoxylem strands in the 
secondary stolon, though it is clear that one of the four protoxylems 
of the primary stolon is continued into the secondary, while serial 
transverse sections in the region of branching lead to the belief 
that the further branching of this strand is on the same general 
plan as in N. volubilis. 
1 Boodle, l.c., p. 366, fig. 4, pi. xix. 
J Poirault, Ann. Sci. Nat. VII, t. 18 t p. 250 ff. 
* Sperlich, l.c., p. 464. 
