FILICINEM. 
Among the Forms of Tissue of the Ophioglossaceae, the prevailing one is parenchy- 
matous fundamental tissue ; there is no sclerenchyma. It consists, especially in the leaf- 
stalk, of long, almost cylindrical, thin-walled succulent cells with straight septa and large 
intercellular spaces; in the lamina the latter are, in O. vulgatum, very large, and the tissue 
spongy. In O. 'vulgatum and B. Lunaria, the epidermal tissue nowhere possesses special 
hypodermal layers; a well developed epidermis with numerous stomata on the upper and 
under side of the leaves immediately covers the outer layers of the fundamental tissue : 
at the periphery of the stem layers of cork are formed. The fibro-vascular bundles of O. 
•vulgatum form, according to Hofmeister, a hollow cylindrical network in the stem, on 
which the leaves are arranged spirally, with a | phyllotaxis ; each of the meshes of this 
network corresponds to a leaf, and gives off to it the foliar bundles from its superior angle : 
the lower end of each foliar bundle terminates in a root. The leaf-stalk is penetrated by 
from 5 to 8 slender fibro-vascular bundles, which, in transverse section, are arranged in a 
circle, and between which the fundamental tissue forms wide lacunae. Each of these 
bundles has on its axial side a strong fascicle of narrow reticulately thickened vessels, a 
broad fascicle of soft bast (phloem) lying on their peripheral side. In the sterile lamina 
the slender bundles branch copiously and anastomose into a network ; they run into the 
mesophyll which contains chlorophyll, without forming projecting veins. The slender 
stem of B. Lunaria has the same structure as that of Ophioglossum ; its vascular bundles 
appear to be only the lower ends of the foliar bundles (Fig. 289), which are arranged in a 
circle in the stem and form a hollow fibro-vascular cylinder consisting of numerous 
xylem-bundles surrounded by a common investment of phloem. In each leaf-stalk, 
which has a conical cavity below obliterated above, arise two broad ligulate bundles, 
which split above, below where the leaf divides into the fertile and sterile laminae, into 
four narrower bundles. Each of these latter consists of a broad axial fascicle of tra- 
cheides thickened in a scalariform or reticulated manner, which is enveloped by a thick 
layer of phloem. This layer shows an inner stratum of narrow cambiform cells, while 
the outside is formed of soft thick-walled bast-like prosenchyma (as in Pteris and other 
Ferns). In the lobes of the sterile lamina the bundles repeatedly split dichotomously, and 
run through the mesophyll without forming projecting veins. 
The ground-tissue either forms no sheath round the fibro-vascular bundles of the 
leaves (Ophioglossum) or it forms a sheath consisting of collenchyma [Botrychium) ; the 
usual bundle-sheath of cells with sinuous walls appears to be wanting. According to 
Russow, the fibro-vascular cylinder formed in the stem of Botrychium by the lower 
portions of the foliar bundles is surrounded by a sheath of this kind (Plerome-sheath). 
He also believes that the fibro-vascular bundles in the stem of Botrychium undergo a 
slight subsequent growth in thickness. In the petiole of Ophioglossum I find, as Russow 
describes, that the thin fibro-vascular bundles have collateral phloem and xylem and that 
the central xylem of Botrychium is surrounded on all sides by phloem. 
[According to Russow, a formation of cork takes place at the surface of the rhizome 
of Ophioglossese ; in this, so far as is known at present, they are unique among Vascular 
Cryptogams.] 
Habit and Mode of Life. The number of leaves which appear each year is small, and 
constant in the species ; thus O. 'vulgatum and B. Lunaria unfold only a single leaf 
annually, B. rutcpfolium two, a sterile and a fertile one ; O. pedunculosum from 2 to 4 
(Mettenius). The extremely slow development of the leaves is remarkable; in B. 
Lunaria each leaf requires four years, of which the three first are passed underground ; 
in the second year the two branches (the sterile and fertile laminae) are formed, and 
further developed in the third; in the fourth year they for the first time rise above 
ground (Fig. 289), the process reminding one of the slow formation of the leaves of 
Pteris aquilina ; the same occurs in O. 'vulgatum. In both genera the formation of the 
sporangia begins a full year before they ripen. 
Vegetati've Reproduction takes place in Ophioglossum by means of adventitious buds from 
the roots. 0. pedunculosum is so far monocarpous that, after the production of fertile 
