392 
VASCULAR CRYPTOGAMS. 
The second generation is a simple or repeatedly branched stem, usually possessing roots 
and always bearing simple, unsegmented, comparatively small, but very numerous leaves, 
which are traversed by only a single fibro-vascular bundle. All the branchings of the 
stem and of the roots present the appearance of having originated dichotomously. 
The sporangia are borne singly upon the upper surface of the base of the leaves, or 
in their axils, or even in an extra-axillary position upon the stem. They originate as 
masses of cells derived in part {Isoetes) from internal tissues, covered by the epidermis 
which forms their walls. The archesporium is multicellular in some cases, unicellular 
in others. 
Order I. Lyeopodiaceae. The prothallia, which are developed from spores of one 
kind only, are capable of independent growth and are monoecious. The roots branch 
dichotomously in alternate intersecting planes, and neither stem nor root possesses 
a single apical cell. The leaves have no ligula. The fibro-vascular cylinder of the 
stem consists of numerous xylem-bundles, each of which is surrounded by phloem. 
Families. (i) Lycopodieae. 
(2) Psiloteae. 
(3) Phylloglosseae. 
Order II. LigulataB. The spores are of two kinds. Each macrospore forms a 
rather large internal female prothallium, the archegonia of which only become exposed 
when the wall of the spore is ruptured. Within each microspore a rudimentary pro- 
thallium completely filling it is formed, certain cells of which give rise to the mother- 
cells of the antherozoids. The second generation is of very different habit in the two 
families. The leaves are always provided with a ligula borne above their base, and 
below this lies the sporangium which contains either numerous microspores or four or 
more macrospores. 
Families. (i) Selaginellese. 
(2) Isoeteae. 
CLASS VII. 
EQUISETINE/E^ 
The Sexual Generalion (Oophore). The spores of the Equisetaceae, so soon as 
they have attained the ripe condition (they retain their power of germination only 
^ G. W. Bischoff, Die kryptogamischen Gewächse (Nürnberg 1828). — W. Hofmeister, Vergl. 
Unters. (1851). — Ditto, Ueber die Keimung der Equiseten (Abh. der königl. Sachs. Gesell, d. Wiss. 
1855, vol. IV. p. 168). — Ditto, Ueber Sporenentwickelung der Equiseten (Jahrb. für wiss. Bot. vol. III. 
p. 283). — [Germination, Development, and Fructification of the Higher Cryptogamia (Ray Society), 
pp. 267-306]. — Thuret (in Ann, des Sei. Nat. 1851, vol, XVI. p. 31). — Sanio, Ueber Epidermis 
und Spaltöffnungen des Equis, (Linnaea, vol. XXIX. Heft 4), — C. Cramer, Längenwachsthum und 
Gewebebildung bei E. arvense und sylvadaim (Pflanzenphys Unters, von Nägeli und Cramer, 1855, 
vol. III), — Duval-Jouve, Hist. Nat. des Equisetum (Paris 1864). — H. Schacht, Die Spermatozoiden 
im Pflanzenreich (Braunschweig 1864). — Max Reess, Entwickelungsgeschichte der Stammspitze von 
Equisetum (Jahrb. für wiss. Bot. 1867, vol. VI. p, 209). — Milde, Monographia Equisetorum, in Nova 
Acta Acad. Leop. Carolina, 1867, vol. XXXV. — Nägeli und Leitgeb, Entstehung und Wachsthum 
