FILICES 



95 



germination. The wall of the spore is composed of three layers ; the 

 surface is covered by minute wart-like spines. 



Vegetative propagation takes place with great facility in some species 

 of this family. In ^Nlarattia cicutaefolia the leaves, or even the stipules, 

 have only to be cut into small pieces, and placed in damp soil or in a 

 bottle, when a number of adventitious buds will be developed in con- 

 nection with the ' vascular ' bundles. 



The Marattiace^e comprise only a very small number of species, 

 almost entirely confined to the tropics, and included in the four genera 

 Angiopteris (Hoffm.), Marattia (Sm.), Dan^ea (Sw^), and Kaulfussia(Bl.). 

 With the exception of the stipules, and the great thickness of the leaves, 

 they have quite the habit of ordinary ferns. 



Literature. 



De Vriese and Harting — Monographic des Marattiacees, 1853. 



Mettenius — Ueber den Bau von Angiopteris, 1863. 



Luerssen — Mittheil. aus dem Gesammtgebiete der Bot., vol. i., Heft 3, 1872; and 



Bot. Zeit., 1872, p. 768 ; and 1873, pp. 624 and 641. 

 Riissow — Vergleichende Untersuchungen, 1872, p. 185. 

 Holle— Bot. Zeit., 1875, P- 215. 



Jonkman — Bot. Zeit., 1878, p. 129; and Archives Xeerland., 1S80. 

 Schenk— Ber. Deutsch. Bot. Gesell., 1S86, p. Z(i. 



Class v.— Ophioglossaceae. 



This small but very well-defined group, although popularly included 

 with the Filices under the common denomination of ferns, differs from 

 them in several important points of structure, in some of which a con- 

 necting link is furnished by the Marattiacese. The prothallium is under- 

 ground and destitute of chlorophyll, exhibiting a similarity to that of 

 Lycopodiaceae rather than to that of true ferns. The stem rarely at- 

 tains more than a few inches in height, and usually does not branch ; it 

 is remarkable for its slowness in growth. It contains no sclerenchy- 

 matous layers. The leaves are not circinate in vernation, and the 

 petiole is furnished at the base with lateral outgrowths, which have 

 been compared to the stipules of Marattiacese. The venation is dicho- 

 tomous or reticulate, and generally inconspicuous. The sporanges are 

 completely endogenous in their origin, and are never borne on the under 

 side of the green leaf, but on a separate branch of the leaf, altogether 

 destitute of green parenchyme, and form a compound 'fructification,' 

 resembling in appearance a spike or panicle : there is no annulus. The 



