RHIZOCARPE.E. j^. 



Ha/fit and Mode of Life. The number of leaves which appear each year is small and 

 constant in the species; thus O. i<ulgatum and B. Limaria unfold only a single leaf 

 annually, B. rutafolium two, a sterile and a fertile one; O. pedimculosum from 2 to 4 

 (IMettenius). The extremely slow development of the leaves is remarkable; in B. 

 Liinaria each leaf requires four years, of which the three first are passed underground • 

 in the second 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. 283), the process reminding one of the slow formation of the leaves of Pteris 

 aquilinai the same occurs in O. 'vulgatum. 



Fegetati've Reproduction takes place in Ophioglossum by means of adventitious buds 

 from the roots. O. pedimculosum is so far monocarpous that, after the production of 

 fertile leaves, it as a rule dies down, but maintains a perennial existence by means of 

 the root-buds (Hofmeister). Most species are only, reckoning from the base of the 

 stem to the apex of the leaf, 5 or 6 inches high; a few attain the height of a foot; 

 B. lanuginosum of the East Indies is stated by Milde to be 3 feet high; the leaf is three 

 or four times pinnate, and the stem contains from 10 to 17 fibro-vascular bundles. 



CLASS IX. 



RHIZOCARPE^^ 



1. The Sexual Generation of Rhizocarps is developed from spores of two 

 different kinds; the smaller spores produce antherozoids, and are therefore male; 

 the larger spores, which exceed the smaller kind several hundred times in size, 

 produce a small prothallium, which never separates from them, and forms one or 

 several archegonia ; the macrospores may therefore be considered to be female. 



^ G. W. Bischoff, Die Rhizocarpeen u. Lycopodiaceen (Niirnberg 1828).— Hofmeister, Vergleich. 

 Untersuch. 1851, p. 103.— [On the Germination, Development, and Fructification of the Higher 

 Cryptogams, Ray Soc. 1862, pp. 318-335.]— Ditto, Ueber die Keimung der Salvlnia 7iata?is (Abhand. 

 der kOnigl. S'ichs. Gesellsch. der Wissensch. 1857, p. 665).— Pringsheim, Zur Morphologic der Sal- 

 vinia natans (Jahrb. fur wissensch. Bot. vol. HI. 1863).— J. Hanstein, Ueber eine neuholLindische 

 Marsilia (Monatsber. der Berliner Akad. 1862, Ann. des Sci. Nat. 4th series, vol. XX, 1863, 

 pp. 149-166).— Ditto, Befiuchtung u. Entwickelung der Gattung Marsilia (Jahrb. fiir wissensch. 

 Bot. vol. IV, 1865).— Ditto, Pilulariffi globuliferee generatio, cum Marsilia comparata (Bonn 1866). 

 — Nageli u. Leitgeb, Ueber Entstehung u. Wachsthum der Wurzein bei den Gefasskryptogamen 

 (Berichte der bayer. Akad. der ^Vissensch. 1866, Dec. 15, and Nageli's Beitrage zur wissensch. Bot. 

 vol. IV. 1867).— Millardet, Le Prothallium male des Cryptogames vasculanes (Strasbourg 1869). 

 -A. Braun, Ueber Marsilia u. Pilularia (Monatsber. der konigl. Akad. der Wissensch^ Berlin, Aug. 

 i87o).-E. Russow, Histologic u. Entwickelung der Sporenfrucht von Marsilia (Dorpat 1871). 

 [Strasburger, Ueber Azolla, mit 7 Tafeln. Jena 1873.] 



