34^ MUSCINEJE. 



CLASS V. 

 H E PATIC^i. 



(i) The Sexual Generation (Oophore) is developed, in some genera, directly 

 from the germinating spore, its first divisions resulting in the formation of a cellular 

 lamina or a mass of tissue which fixes itself by root-hairs and produces the thallus 

 by growth at its apex, as in Anihoceros and Pellia. In other cases the body which 

 results from the divisions of the spore first forms a narrow ribbon-like lamina of 

 cells, the apical cell of which becomes subsequently the apical cell of a stem, and 

 its segments form leaves, as in Jungermannia bicuspidata (according to Hofmeister). 

 Or again, the bud of a leafy stem springs immediately from the spore {Frullania 

 dilatatd). In other cases, on the other hand, a protonema is formed ; the endospore 

 which grows out into the form of a tube produces a short articulated filament on 

 which the rudiments of the thallus are formed as lateral shoots, in a manner similar 

 to the leaf-buds of Mosses on the protonema {e.g. Aneura palmaia^ Marchantia). 

 In Radula the spore produces first of all a flat plate of cells, from which the first 

 bud of the leafy stem springs laterally (Hofmeister), a process which finds its ana- 

 logue among Mosses. 



The vegetative body of Hepaticae is always formed in a distinctly bilateral 

 manner; its free side, turned towards the light, is differently organised from that 

 which faces and often clings closely to the substratum and is not exposed to light. 



In the greater number of families and genera the vegetative body is a broad, 

 flat or curled plate of tissue, varying in length from a few millimetres to several 

 centimetres ; and is either a true thallus without any formation of leaves, as in 

 Anthoceros, Meizgeria, and Aneura, or lamelliform outgrowths arise on the under 

 or shady side, which at the same time produces root-hairs ; and these outgrowths 

 may be looked on as leaves. For the sake of having a common expression for these 

 forms extremely similar in habit, they may be comprised under the term Thalloid'^, 



^ Mirbel, Ueber Marchantia, in the Mem. de I'Acad. des Sci. de I'lnst. de France, vol. XIII, 

 1835.— G. W. Bischoffjin Nova Acta Acad. Leopold. Carol. 1835, vol. XVII. pt. 2.— C. M. Gottsche, 

 ibid., vol. XX. pt. i. — Gottsche, Lindenberg u. Esenbeck, Synopsis Hepaticarum, NUrnberg, 1844. — 

 Hofmeister, Vergleich Untersuchungen, 1851. — [On the Germination, Development, and Fructifica- 

 tion of the Higher Cryptogamia : Ray Society, 1862.] — Kny, Entwickelung der laubigen Lebermoose ; 

 Jahrb. fiir wiss. Bot. vol. IV. p. 66, and Entwickelung der Riccien, ibid., vol. V. p. 359. — Thuret, in 

 Annal. des Sci. Nat. 1 851, vol. XVI (Antheridia).— Strasburger, Geschlechtsorgane u. Befruchtung bei 

 Marchantia; Jahrb. fiir wiss. Bot. vol. VII. p. 409: [also Befruchtung und Zelltheilung, 1878]. 

 — Leitgeb, Wachsthumsgeschichte der Radula cotnplanata ; Sitzungsber. der Wiener Acad. 1871, 

 vol. LXIII. — Ibid., Bot. Zeitg. 1871, no. 34, and 1872, no. 3. — A portion of what is said about the 

 apical growth of Jungermanniese is derived from communications by letter from Leitgeb. — Janc- 

 zewski, Bot. Zeitg. 1872. — [Leitgeb, Unters. ueb. Lebermoose, 1874-78. Goebel, Zur vergl. Anat. 

 der Marchantieen, Arb. d. bot. Inst, in Wiirzburg, II. 3, 1880.] 



^ [The term 'thalloid' is here, as on p. 342, preferred to the one in more general use, 

 ' frondose.'] 



