Ophiogiossum ( Cheiroglossd ) palmatum , L. 295 
structure in the family at large. But these must be left over at the moment. 
It is obvious that there are difficulties in assigning any definite place to the 
family at present. But sufficient has been said to show how clearly the 
balance of evidence is setting in the direction of an alliance of the Ophio- 
glossales with the early Filicales. 
A natural consequence of adopting a Filical alliance for the Ophioglos- 
saceae would be a recognition of the pinna-nature of the spike, probably in 
most cases with a coalescence of two pinnae as in the old theory of Roeper. 
I should, however, attach less weight in arriving at this conclusion to such 
abnormalities as those quoted by Dr. Chrysler than he appears to do. 1 For 
branchings of very various character may be found, which all deserve equal 
consideration with those which support a hypothesis of fusion. The analogy 
with the Marsiliaceae also becomes obvious. But probably the condition 
there seen is an instance of parallel development, and arises along a different 
phyletic line. For the two families belong to distinct types of Fern- 
development. The Ophioglossaceae appear to be naturally referable to the 
Coenopterid 2 type, characterized by less definite specialization of the 
sporangium. But the Marsiliaceae are pronouncedly Leptosporangiate, and, 
as Campbell has so convincingly shown, their relations appear to be in the 
direction of the Schizaeaceae. 3 
Summary. 
1. The tuberous stock of Ophiogiossum palmatum is traversed by a stele 
showing a bulky central pith and transversely widened leaf-gaps. It is of 
the same type as Etc-Ophioglossum. 
2. The leaf-trace originates as two distinct strands inserted widely 
apart, right and left of the leaf-gap. 
3. The spikes originate like that of Eu-Ophioglossum. The lowest is 
usually median, but not always. The insertion of the rest is usually intra- 
marginal, and shows no regular alternation. The spikes branch frequently 
and irregularly. 
4. The facts indicate that the spike of Eu- Ophiogiossum is the morpho- 
logical unit, and that the conditions seen in less degree in O. pendulum , and 
more clearly in O. palmatum, are due to ‘pleiogeny’, that is an increase 
from that unit in various ways, such as by partial or completed branching, or 
by interpolation of accessory spikes. The numerous spikes of O. palmatum 
are not then directly referable to normal pinnae, any more than are the 
irregular lobes of its sterile lamina. 
5. Phyletically O. pendulum, intermedium , and simplex form a derivative 
series from Eu- Ophiogiossum l O. palmatum represents a parallel, but pro- 
bably a distinct line, which has carried amplification of the leaf further. 
1 loc. cit. , pp. 7-9 and PI. II. 2 Seward, Fossil Plants, ii, p. 433. 
3 Campbell, American Naturalist, xxxviii, 1904, p. 761. 4 See Land Flora, p. 441. 
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