410 
VASCULAR CRYPTOGAMS. 
education a field for work is here open. We must content ourselves now with briefly- 
stating all that is actually known, and with merely mentioning the less known forms 
when occasion demands. 
Order I. Stipulate. 
Under this name, which is based upon the peculiar formation of stipules common 
to the members of the two groups, I include the Ophioglossese and the Marat- 
tiaceae, for the relationship existing between them is manifested in several important 
particulars. In both groups the prothallia are monoecious and capable of inde- 
pendent growth ; but there is a tendency to dioecism in the Marattiaceae. That the 
prothallia of the Ophioglossese are subterranean, whereas those of the Marattiaceae 
are not so, is a difference of physiological and not of morphological importance. The 
stem of the second generation in both families is characterised by its very slight 
growth in length, the usual absence of internodes and of any branching, the whole of 
its surface being occupied by the insertions of the leaves, and by the development of 
roots acropetally immediately behind its apex. The absence or rudimentary deve- 
lopment of bundle-sheaths and of brown schlerenchyma in the ground-tissue of the 
stem and of the leaves distinguishes these plants from the true Ferns. The Ophio- 
glossese diverge most widely from the Ferns in that their sporangia are imbedded in 
the tissue of the leaf. The Marattiaceae present an intermediate condition in that 
their sporangia are quite external to the leaf and are attached by a narrow base. 
Although it is not improbable, it is still an open question whether or not the 
Osmundaceae are nearly related to these two families. Their petioles bear at their 
bases lateral membranous wing-like appendages which may fairly be termed stipules, 
but which are certainly very different from those of the Marattiaceae and Ophio- 
glosseae. Further, the stem of the Osmundaceae, which is thickly covered with roots, 
is not erect like that of the other two groups, and it is uncertain whether the 
numerous lateral branches arise from it or from the petioles of the leaves. The 
fructification seems to indicate a relationship, for it recalls the paniculate fructifi- 
cation of the Botrychiae, but the fertile segments of the leaves have no mesophyll. 
In this respect the Schizaeaceae resemble the Osmundaceae, but in other features, 
more especially in the want of stipules, they differ from the Stipulatae. 
Although the connection of the Ophioglosseae with the Marattiaceae is tolerably 
evident, it may be advisable to give a separate account of each family. 
Family I. Ophioglosseae-. The Sexual Generation (Oophore). The pro- 
thallium is at present known only in Ophioglossum pedunculosum and Botrychium 
Lunaria. In both cases it is developed underground. It is destitute of chloro- 
phyll, and forms a parenchymatous mass of tissue which, according to Mettenius, 
has at first, in the species first-named, the form of a small round tuber, out 
^ Mettenius, Filices horti botanici Lipsiensis, Leipzig 1856, p. 119. — Hofmeister, Abhandlungen 
der königl. Sächs. Gesellsch. der Wissens. 1857, p. 657. — [On the Germination, Development and 
Fructification of the Higher Cryptogams, Ray Soc. 1862, pp. 307-317.] — Russow, Vergleich. Unters. 
St. Petersburg, 1872, pp. 117 ff, ~ [Holle, Ueb. Bau und Entwickelung der Vegetationsorgane der 
Ophioglos3en, Bot. Zeitg. 1875.] 
