322 



The most remarkable point of structure in Hepaticee is the spiral filament, as 

 it is called, lying among the sporules within the theca. This consists- of a 

 single fibre, or of two, twisted spirally in different directions, so as to cross each 

 other, and contained within a very delicate, transparent, perishable tube. They 

 have a strong elastic force, and have been supposed to be destined to aid in the 

 dispersion of the sporules, — a most inadequate end for so curious and unusual 

 an apparatus. It is more probable that they are destined to fulfil, in the econo- 

 my of these plants, some function of which we have no knowledge. Hepa- 

 ticse are intermediate between Mosses and Lichens, agreeing with the former in 

 the presence of a distinct axis of growth, and frequently of leaves also, and in 

 most cases in the sporules being contained in stalked thecs, having a calyptra 

 and a definite mode of dehiscence. Fee says they have no calyptra, which must 

 have been an oversight. They differ from Mosses in the want of an operculum, 

 by which Andraea, which forms the link between Hepaticse and Mosses, is re- 

 ferred to the latter. Lichens are distinguished by their want of a distinct axis 

 of growth, by their texture and color, never assuming the rich lucid green of 

 Hepatic^, and by their sporules not being contained in distinct thecal, but lying 

 in membranous tubes or asci in the substance of the- thallus. Riccia and 

 Endocarpus form the connexion between them. 



Geography. Natives of damp shady places in all climates; two were 

 found in Melville Island. The only atmospheric condition to which they can- 

 not submit is excessive dryness : thus, of the 237 species enumerated by 

 Sprengel, 6 only are found in Africa, while 50 are cited from Java alone. 



Properties. Nothing is known of them. Decandolle thinks it probable 

 that the larger kinds will be found to resemble foliaceous Lichens in their qua- 

 lities. A few are slightly fragrant. 



Examples. Marchantia, Targionia, Sphasrocarpus, Jungermannia. 



CCLXIX. CHARACE.E. The Chara Tribe. 



Characeje, Rich, el Kunth in Humb. ct Bonpl. N. G. PL 1.45. (1815) ; A. Brongn. in Did. 

 Class. 3. 474. (1823); Grev. Fl. Edin. xvii. (1824); Dec. and Duby, 533. (1828): Hooker 

 Brit.Fl. 459. (1830.) 



Diagnosis. Submersed leafless water-plants, having slender verticillale 

 branches and deciduous thecee. 

 Anomalies. 



Essential Character. — Plants composed of an axis, consisting- of parallel tubes, which 

 are either transparent or encrusted with carbonate of lime, and of regular whorls of tubes, 

 which may be either considered as leaves or branches. Organs of reproduction, round succu- 

 lent globules, containing filaments and fluid ; and axillary nucules, formed of a few short 

 tubes, twisted spirally around a centre, which has the power of germinating. 



Affinities. The two genera of which this little order is composed are 

 among the most obscure of the vegetable kingdom, in regard to the nature of 

 their reproductive organs ; and accordingly we find them, under the common 

 name of Chara, placed by Linnaeus among Cryptogamous plants near Lichens ; 

 then referred by the same author to Phamogamous plants, in Monoecia Monan- 

 dria ; retained by Jussieu and Decandolle among Naiades, by Mr. Brown at the 

 end of Hydrocharidese, and by Leman in Haloragese ; referred to Confervas by 

 VonMartius, Agardh, and Wallroth ; and finally admitted as a distinct order, 

 upon the proposition of Richard, by Kunth, Decandolle, Adolphe Brongniart, 

 Greville, Hooker, and others. Such being the uncertainty about the place of 



