5S 



MARCHANTIACE^. 



[ACROGENS. 



Order XVI. MARCHANTIACEiE.— Liverworts. 



Hepaticse, Juss. Gen. 7. (1789) 

 Esenb. in Martius, Fl. Bras 



; DC. Fl. Fr. 2. 415. (1815) ; Agardh Aph. 104. (1822) ; Nees ab 

 1. 2y.5. (1833) ; Hooker's British Flora, vol.ii. p. 97. (1833) ; Bischoff 



2 



de Hepaticis in Act. Acad. I^at. C(/r. xvii. pars 2. (1836); Ann. des Sc.2. 5f>-. 4. 309. (1836).— 

 Marchantiacese and Targioniaceae, Ed. pr. Endl. Gen. xx. — Marchantieae and Taxgioniese, 

 Nees Lebermoose, 84.— Marchantieae, Taylor in Linn. Trans. 17. 377. 

 Diagnosis. — Spoi'e-casesvalTeless,orliu'stmg irregularly, withoittoperculum^l'utwithelaters. 

 Plants groM-ing on the earth or ti'ees in damp places, composed entirely of cellular 

 tissue, emitting roots from theu* under-side, and consisting of an axis or stem which 

 is leafless, but bordered by membranous expansions, which 

 sometimes unite at then- margins, so as to form a broad lobed 

 frond, ha\Tng a distinct epidermis pierced by stomates. An- 

 theridia either immersed in the frond, or placed on disk-like 

 sessile or stalked peltate receptacles. Pistilhdia Im-king within 

 mvolucres, either placed below the edge of the frond, or on the 

 edge or under-side of stalked heads. Spore-cases stalked, open- 

 ing by UTegular fissures, or by separate teeth. Spores globose, 

 with elators. 



With these plants organization advances another step. To the 

 spores of the Crystalworts are added spiral threads or elaters 

 for their dispersion ; and various lacerated membranes sur- 

 ounding the spore-cases seem to be imitating the calyx and 

 corolla of perfect plants. There is still, however, a want of 

 true leaves, which are fused, \\\i\\ the stem, into a 

 _ frond. The principal part of the order has the spore- 



cases raised on a long stalk, and clustered into a head ; 

 but this character is missing in Tai'gionese, which 

 Endlicher regards as a distinct order. In these 

 plants, as in Mosses and Charas, each cell of what 

 are called the antheridia contains a body resemliling 

 an animalcule of the genus Vibrio, which moves about 

 rapidly in water, as soon as it is hberated from its 

 birth-place. Germination takes place by an universal 

 increase and enlargement of the spore, which becomes 

 lobed, as it were, by the swelling of the cellules, and 

 is afterwards nom'ished by the emission of a radicular 

 fibre. The original development o 1 Ferns and Liverworts is much the same. Fl. Bras. 

 i. 299. 



The Liverworts differ from Crystalworts in having elaters and involucrate spore-cases, 

 and from Scalemosses or Jungennanniacese, in the want of power to separate their spore- 

 cases mto distinct valves. 



Natives of damp shady places in all chmates ; two were found in Meh-ille Island. 

 The only atmospheric condition to which they cannot submit is excessive dryness. 



Little is known of then- uses. De Candolie thinks it probable that the larger kinds 

 will be found to resemble foliaceous Lichens in theu' quahties. A few are slightly 

 fragrant, with a subacrid taste. They have been employed in liver complaints, but their 

 use seems a mere superstition. It is, however, alleged that Marchantia hemisphserica 

 has really proved advantageous in dropsical affections. 



Fig. XXXVIII. 



Suborder I. Marchax- 

 T£^. --Spore-cases capi- 

 tate. Involucels mem- 

 branous, regularly slit. 



Grimaldia. Radd. 



Pleurochiton, Radd. 



Syndonisce, Radd. 



Mannia, Cord. 

 Duvalia, Nees. 

 Petalophyllum, Nees. 

 Fimbriana, Nees. 



Hypenantron, Cord. 



I>ictyoch)ton, Cord. 

 Fegatella, Radd. 



Conocephalus, Vaill. 



Cynocephalum, Wigg. 

 Lunularia, Michel. 



Sedgicichia, Bowd. 

 Plagiochasma, Lehm. 



Otiona, Cord. 



Sedguickia, Bisch. 



Aitonia, Forst. 



Ruppinia, L. f. 

 Antrocephalus, Lehm. 

 Rebouillia, Radd. 



ERA. 



Asterella, Palis. 



Rhakiocarpon , Cord. 



Achiton, Cord. 



9 Mesoregma, Cord. 

 Sauteria, Nees. 



Hampca, Nees. 

 Dumortiera, Nees. 



Hyrophila, Mack. 



Hygrophyla, Tayl. 



? Spathysia , Nees. 

 Marchantia, March. 



Astromarchantia, Ne( 



Chlamidium, Cord. 



Preissia, Nees. 



Chomiocarpon, Cord. 



Suborder II. Targione,«. 

 — Spore-cases submar- 

 ginal, solitary. Involu- 

 cels wanting. 



Targionia, Michel. 

 Cyathodium, Lehm. 

 ? Carpobolus, Schwein. 



Numbers. Gen. 15. Sp. 20 ? 



Equisctaccce. 

 Position. Ricciacese. — Marchantiace^. — Jungermanniacese. 

 Lickenacece. 



Fig. XXXVIII. — 1. Marchantia commutata, natural size : 2. a head of spore-cases ; 3. a section of 

 the disk which bears the spore-cases ; 4. elater ; 5. granular spore. 



