1 8 Boiver. — Studies in the Phytogeny of the Filicates. VI. 
of success on the basis of habit of vascular anatomy, of dermal appendages, 
and of sori and sporangia. Unfortunately it cannot be extended to the 
gametophyte, since this is not yet known either in L. tricuspis or in 
Neocheiropteris. As regards habit, the sections Phlebodium and Phymatodes 
are, like Neocheiropteris and L. tricuspis , rhizomatous, with usually a fleshy 
texture of the stock and broad dermal scales. The leaves are arranged in 
alternate sequence and long-stalked. The lamina is not finely divided, but 
shows few lobes or graduates by omission of the lobing to the entire 
condition, which is the case for many of the species of Phymatodes. These 
steps, seen either on comparison of individuals or species, present interesting 
features. A good case is seen in Polypodium (. Phymatodes ) decumanum. 
Plate I, Fig. 6 shows a three-lobed leaf, readily referable to the same analysis 
of branching as that given above for L . tricuspis , but here the interpretation 
is more obvious, since the forking to form the left-hand pinna is distinctly 
below the second forking which gives the median and right-hand lobes. 
A simpler state in the same species is seen in Plate I, Fig. 7, where only 
two lobes are developed, the third being rudimentary, but still recognizable at 
the base of the right-hand lobe. Such examples support the interpretation 
of the ternate leaf of L. tricuspis as derived by two successive dichotomies. 
They may readily be multiplied by examination of herbarium series of the 
species of Phymatodes . 
On the other hand, the number of the lobes is often greater than three, 
as in P . aureum and in many species of Leptochilus. But these more com- 
plex leaves are merely the result of repetition of that same branching which 
gives the ternate leaf, so as to constitute a scorpioid sympodium. The 
result may be the pinnatifid or pinnate leaf typical of so many species 
of Phlebodium , Phymatodes , or Leptochilus . An interesting feature which 
they show not unfrequently is a helicoid branching in the basal pinnae. 
This is illustrated in Plate II, Fig. 8, for Leptochilus latifolius (Meyen), C. Chr. 
It is shown even more prominently in pinnae of the fertile leaf, where a third 
helicoid branching has been observed. Such branchings, when compared 
with those of N eocheiropteris or L . tricuspis , may be held as reminiscent of 
the helicoid sympodial branching, as seen in the leaf of Matonia . Thus it 
is possible to refer the construction of the leaves of Phymatodes , Phlebodium , 
and Leptochilus to the modification of a type of construction such as is seen 
in the Matonia-Dipteris series, the modification being in the direction 
of simplification. Neocheiropteris provides an important intermediate type. 
The chief modifying factors appear to have been reduction in the number of 
forkings of the adult leaf, and the substitution of a scorpioid for a helicoid 
development of them. 
Comparison on the basis of vascular anatomy presents certain difficulties 
which had already become apparent in the case of Cheiropleuria , 1 This 
1 See Ann. of Bot., vol. xxix, p. 497, &c. 
