Bower. — Studies in the Phytogeny of the Filicales. VI. 19 
Fern, though it has an advanced sorus of * mixed * Acrostichoid type, is 
protostelic, like Gleichenia , but with a leaf-trace which forks at once after 
departure. The Matonioid-Dipterid alliance is solenostelic with undivided 
leaf-trace. But we find Neocheiropteris to resemble Leptochilus tricuspis in 
having its vascular system much broken up by ‘ perforations ’, both in leaf- 
stalk and in axis ; and this advanced vascular state accords with their 
advanced type of sorus. But the facts for Cheiropleuria show that such 
a parallel march of characters is not obligatory. With these facts before us, 
and with already some doubt whether L . tricuspis fits naturally into this 
genus to which it is usually referred, it becomes necessary to know the 
anatomical details of other species of the genus Leptochilus . Mettenius has 
already examined the vascular system of L. axillare , a widely scandent 
species with entire leaves. 1 He found the leaf-trace to consist of two 
strands, and the stele of the axis broken up into isolated strands connected 
in elongated meshes (‘perforations’). This is the only statement I have 
found relating to the stelar anatomy of the genus, though he describes the 
structure for four species now ranked under E laphoglossu m . 2 
Among material of several species of Leptochilus which was available 
for investigation that of L. nicotianaefotius , collected in Jamaica, was selected 
as having a robust rhizome, with leaves alternating in two rows, separated 
by relatively long internodes, and inserted obliquely on its upper surface- 
Irregularly disposed on its flanks are slightly projecting pneumatophores 
with spongy tissue, which lie along the margins of the sections. The base of 
the petiole is traversed by about eight vascular strands, arranged in a horse- 
shoe, with the gap facing acroscopically, and on each side of it a strand of 
larger size. In this it corresponds to L. tricuspis and to Neocheiropteris , 
allowance being made for variation in number of the strands. But transverse 
sections of the stock show constantly present a broad and continuous 
vascular strap on the lower side of the ring, which varies slightly in its 
position and in its relations to the other strands. Less distinctly a narrower 
strap is seen on the upper side. To ascertain the relations of these the 
vascular system has been followed through two successive leaf-insertions, and 
the internode between them : and its successive phases are represented 
in Text-fig. 9, 1-32, which show the relations of the leaf-gaps, and of the 
strands of the leaf-traces to these two larger vascular tracts. 
It will be seen on reading the series in succession that three leaf-gaps 
are involved. These have been identified by the letters W, X, Y, in the suc- 
cessive sections, and where the completed leaf-trace is fully separated from 
the stelar tracts, a dotted line of demarcation has been drawn, as in Nos. 6- 
9 and 26-29. These marks help the identification of the vascular tracts. 
It will be seen that the details are not uniform, a fact that makes some 
1 Abhandl. K. Sachs. Ges. d. Wiss., 1863, p. 554, Taf. IX, Fig. III. 
2 l-c.,pp. 54 6 ~7- 
