192 MARSILEACEAE [ch. xxiii 



The three living genera may be best seriated according to the complexity 

 of their leaves, viz: 



(i) Marsz/ea (Linnaeus, ly S3) ••• 56 species. Leaves 4-lobed. 



(ii) Regnellidiuni (Lindman, 1904) ... i species. Leaves 2-lobed. 



(iii) Pilularia (Linnaeus, 1753) ... 6 species. Leaves unbranched. 



The features of advance which the sporocarp of the Marsileaceae possesses 

 over the sporophyll of the Schizaeaceae do not consist only in Heterospory. 

 The sori also show indications of gradate succession and even of mixed 

 interpolation of sporangia. There is, however, no evidence of the Mar- 

 sileaceae having led to any higher type of organisation, notwithstanding 

 these advanced features. 



BIBLIOGRAPHY FOR CHAPTER XXIII 



459. HOFMEISTER. Higher Cryptogamia, Engl. Edn. Ray Soc. 1862. 



460. Hanstein. Pringsh.-Jahrb. iv. 1865. 



461. Russow. Vergleichende Untersuchungen. St Pdtersbourg. 1872. 



462. Leitgeb. Sitz. d. k. Akad. der Wiss. Bd. Ixxvii. 1878. 



463. Baker. Fern Allies. London. 1887. Here the systematic treatment up to its date 

 is given. 



464. Luerssen. Rab. Krypt. Flora, iii, p. 606, 1889 : with full references to the systematic 

 literature. 



465. Duncan Johnson. Marsilea, Ann. of Bot. xii. p. 119. 1898. 



466. Duncan Johnson. Pilularia, Bot. Gaz. xxvi, p. i. 1898. 



467. Engler & Prantl. Natiirl. Pflanzenfam. i, 4, p. 403, 1902. Here the literature is 

 fully quoted. 



468. Lindman. Ark. f. Bot. iii, 1904. Rec^nellidium. 



469. Seward. Fossil Plants, ii, p. 473. 1910. 



470. Allison. .Sporocarp in M.polycarpa, New Phyt. x, p. 204. 191 1. 



471. Bower. Leaf-Architecture, Trans. Roy. Soc. Edin. Ii. 191 6. 



472. Goebel. Organographie, 2te. Aufl. ii, Teil, p. 1134. 1918. 



473. Campbell. Mosses and Ferns, 3rd. Edn. p. 417, 191 8. Here the literature is fully 

 quoted. 



474. Bower. Studies VII, Ann. of Bot. xxxii, p. i. 1918. 



475. Bower. Primitive Spindle, Proc. Roy. Soc. Edin. Oct. 1922. 



