274 The Anatomy of Nephrolepis volubilis J.Sm. 
absorbing system of the mother-plant) the lateral plant of N. cordi- 
folia (and perhaps of other species) in its ontogeny omits some of 
the earlier stages in stelar evolution which are shown by the 
sporeling (see pp. 260 and 263). 
The Botany School, 
Cambridge, 
September, 1915. 
EXPLANATION OF PLATE IV. 
Illustrating Mr. Sahni’s Paper on the Anatomy of Nephrolepis, 
(The figures are all from photographs). 
1. N. volubilis. Transverse section of mature primary stolon, showing 
on the left the strand of a secondary stolon. Small-celled lignified outer 
cortex. Innermost cortical walls extremely thick, containing phloba- 
phene, seen as a black ring round the stele. Protophloem, a continuous 
wavy layer passing round the eight protoxylems. Phloem filling the bays in 
the xylem-cylinder, and separated from the tracheides by parenchyma. 
X abt. 24. 
2. N. volubilis. Part of transverse section of young primary stolon. Thin- 
walled inner cortex with triangular inter-spaces. The phlobaphene-containing 
walls comparatively thin. In three of the endodermal cells the “ struts ” 
(p. 256) are seen, two having become free by their inner ends, s, sieve-tubes; 
t, metaxylem tracheides which are yet thin-walled, only the protoxylem 
elements being lignified. x abt. 130. 
3. N. volubilis. Transverse section of petiole. Small dorsal strand and 
larger ventro-laterals. In all the xylem is crescentic, with phloem in the 
bays. Cortex as in Fig. 1. x 50. 
4. N. volubilis. Vertical longitudinal section of chalk-gland, showing the 
“ spoon ” shape. Regularly arranged epidermal cells in saucer-shaped 
depression. The gland is made up of swollen reticulate tracheides with 
parenchymatous cells between. The large black bodies may be resinous, but 
some of them are nuclei. 
5. N.Duffii. Transverse section of forking stolon, with a root-strand 
above the strands of the arms of the fork. Each of the latter has four 
protoxylems with phloem in the bays. The root-strand has been given off 
from the strand on the right one of whose protoxylems is stunted, x abt. 45. 
6. N. ramosa (dried material from Kew Herbarium). Transverse section 
of rhizome showing two meristeles in dorso-ventral plane , with leaf-gaps, one of 
which is subtended by the arc-like trace. Sclerenchyma (black) surrounds 
each meristele, one of which has its xylem interrupted (see p. 265, footnote). 
X 45. 
7. N. altescandens (dried material from Kew Herbarium) Transverse 
section of rhizome at a point where a leaf-trace (left) and a branch-trace 
(right) happen to arise at the same time. Leaf-trace consists of two separate 
strands constricted off from cauline meristeles. The attenuated portion of the 
xylem on the right will pass out as the C-shaped branch-trace, x 40. 
8. N. altescandens. Transverse section of rachis, showing arc-like strand 
with its adaxial ends turned outwards. On the right is a pinna-trace, s, a 
peltate ramental scale ; h, hairs, x 40. 
