232 Wigglesivorth . — The young Sporophytes of 
round the stem, and owing to the dorsiventrality of the latter, three different 
kinds must be distinguished, exposed to different degrees of light, moisture, 
&c., namely, dorsal, ventral, and lateral leaves. The ventral leaves are 
narrow, and gradually taper to a point ; a very small portion of the leaf 
is free from the stem, the remaining part is fused with it in such a manner 
that the division between the two is at once lost sight of, and the whole 
ventral side of the shoot appears slightly concave. 
The dorsal leaves are also long and narrow, but the tapering near the 
apex is more sudden than in the ventral leaves, and the portion of the leaf 
fused with the stem projects from the surface of the shoot until it is hidden 
by the free part of the next leaf below. 
The lateral leaves are arranged in pairs almost opposite to each other ; 
they are keeled, and only a very small portion of the leaf is free from the 
stem. The free portion tapers gradually to a point, and is triangular in 
transverse section ; the fused portion is extensive, and appears to form the 
chief assimilating organ. 
Comparing the distribution of stomata on the leaves of the mature 
plant and -those of the young sporophyte, it appears that whereas on the 
latter the stomata are scattered in about equal numbers on both surfaces, 
in the former their distribution is restricted to certain areas. On the outer 
side of the ventral leaves stomata occur only on the basal portion, while 
on the inner side they are scattered over the surface, almost extending to 
the apex. On the outer side of the dorsal leaves stomata are absent, while 
on the inner side they are restricted to a small area a short distance below 
the tip. In the case of the lateral leaves, three surfaces must be considered 
— upper, under, and inner, the two former representing the outer surface of 
the leaf. On the under side numerous stomata occur near the base of the 
free portion, especially on that part which lies nearer the stem, and on the 
fused portion except near the outer edge. Stomata are absent on the upper 
side, but are present on the inner surface of the leaf. The vascular bundle 
does not appear to differ materially from that of the aerial leaves of the 
young sporophyte described above. 
Summary. 
The main results obtained during this investigation may be summarized 
as follows : — 
1. The first root of the young sporophytes of L. complanatum and 
L. clavatiini may show a monarch, diarch, and triarch arrangement in the 
same plantlet ; the xylem groups are usually separated by phloem, which 
occupies the centre of the stele and extends between the xylem groups to 
its periphery. 
2. The second and following roots show a diarch arrangement, except 
the fine ramifications, which are monarch. 
