38 VASCULAR CRYPTOGAMS 



Plants. The sporocarps of M. Drummondii (Br.), and probably of some 

 other species, are eaten by the natives of Australia under the name of 

 nardoo. 



Literature. 



Bischoff — Die Rhizocarpeen und Lycopodiaceen, Nuremberg, 1828. 



Mettenius— Beitr. zur Kenntniss der Rhizocarpeen, 1846; Linnasa, 1847, p. 260; 



and Beitr. zur Botanik, Heft i, 1853; Plantse Tinneanse. 

 Meyen — Nov. Art. Acad. Cjesar- Leopold., vol. xviii., pt. I, p. 253. 

 Hofmeister — Ueb. Keimung der Salvinia, Abhandl. Sachs. Gesell. Wiss. 1857, 



p. 665. 

 Pringsheim — (Salvinia) Jahrb. f. wiss. Bot., vol. iii. , 1863, p. 484. 

 Hanstein — Ueb. eine neuhoUandische Marsilia, Monber. Berl. Akad. , 1862, p. 183 ; 



Befruchtung u. Entwickelung der Marsilia, Jahrb. f. wiss. Bot., vol. iv., 1865, 



p. 107 ; Pilularise geueratio cum Marsilia comparata, Bonn, 1866. 

 Braun— (Marsilia and Pilularia) Monber. Akad. Wiss. Berlin, 1870, p. 653, and 



1872, p. 668. 

 Russow — Vergleich. Unters., Petersburg, 1S72 ; and Hist. u. Entwick. d. Sporen- 



frucht V. Marsilia, Dorpat, 1877. 

 Strasburger — Ueber Azolla, Jena, 1873. 

 Juranyi — Ueb. d. Entwick. d. Sporangien u. Sporen v. Salvinia, Berlin, 1873 > ^n<l 



(Pilularia) Sitzber. Ungar. Akad. Wiss., 1879 (see Bot. Centralbl. , vol. i., i88l, 



p. 207). 

 Berggren — (Azolla) Rev. Sc. Nat., 1 88 1, p. 21. 



Heinricher — (Spores of Salvinia)_Sitzber. Akad. Wiss. Wien, vol. Ixxxv., 1882, p. 494. 

 Goebel— (Pilularia) Bot. Zeit., 1882, p. 771. 



Class II.— Selaginellaceae. 



This class is composed of two genera only, Selaginella (Spring) and 

 Isoetes (L.), resembling one another in the general facts of their life- 

 history, but differing widely in external appearance, and each consti- 

 lutmg a monotypic order. We have, again, as in Rhizocarpese, two 

 kinds of spore; the megasporanges and microsporanges are of very 

 similar appearance, and are produced in connection with the leaves. 

 The female prothallium, produced within the megaspore, is a more 

 completely endogenous structure than in any other class of Cryptogams, 

 and is altogether destitute of chlorophyll. From the occurrence in both 

 genera of a foliar structure known as the ligule, the term ' Ligulatse ' 

 is sometimes giyen to the class ; but the character is unsatisfactory; 

 and it will be best to treat the two orders Selaginelkm and Isoetece sepa- 

 rately. 



