86 MR. CHURCH ON THE FORM OF THE 
in an irregular oval or pear-shaped figure, from one extremity of ` 
which an incurved prolongation proceedst. The thickened cells of 
the cortical layer and of the dark sheath are of nearly equal size, 
and far less in transverse diameter than the general parenchyma 
of the stem. They are alike stained black when moistened with 
perchloride of iron, owing to the presence in them of tannin. 
Fig. 1. Fig. 2. 
on A =, MA 7 
Qi oe : 
x 5. x 5. 
Transversesectionofone Transverse sectionofone Transverse section of one 
of the two larger vas- of the two fasciculi of of the two fasciculi of 
cular fasciculi of the the stipes of N. The- the stipes of N. Oreo- 
stipes of Nephrodium lypteris. pteris. 
Filix-mas (var. Bor- 
reri). 
The perchloride of iron, as a general rule, darkens the cortical 
layers and the immediate envelope of the central scalariform 
vessels. 
Fig. 4. 
a, X 5. b, x 5. e, X5. d, x 5. e x5. f x5. 
Lais 
(s (9 (m e 
. VLL LL ~ 
a zx * * * * 
Nephrodium Oreopteris, Hooker. 
Hemestheum montanum, Newman. 
Lastrea Oreopteris, Moore. 
Dr. Ogilvie states that W. Oreopteris has two vascular bundles 
in its stipes, and that there is a tract of dark tissue upon that 
aspect of each bundle which looks towards the axis of the stipes. 
I have dissected numerous large and mature specimens of this 
fern, but have never been able to discover a trace of dark tissue 
bundles in a stipes occurs, so that a section of a stipes may disclose more bun- 
dles at some part of its upper extremity than at its base, and vice versa. In 
Lastrea dilatata (Lophodium multiflorum, Newm.) and its nearest allies, the 
irregularities in this respect are more pronounced than in L. cristata (Loph. 
callipteris). 
+ Throughout the figures in the present paper an asterisk indicates the axis 
of the stem; while the letters x, y, z refer to the dark sheath, to the small 
cells, and to the large scalariform vessels of the vascular bundles, respectively : 
the cortex, if given, is marked w. 
