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Properties. The slight astringency of Polylrichum and others caused 

 them to be formerly employed in medicine, but they are now disused. In the 

 economy of man they perform but an insignificant part ; but in the economy of 

 nature, how vast an end ! 



Examples. There is no settled arrangement of the genera, almost every 

 writer having a method of his own. Much merit is due to several, especially 

 to that of Greville and Arnott, published in the Wernerian Transactions, vols. 

 4 and 5. 



Sphagnum, Hypnum, Bryum, Fontinalis, Gymnostomum, Dawsonia, We- 

 issia, Phascum. 



CCLXVIII. HEPATICyE. The Liver-wort Tribe. 



Hepatic*, Juss. Gen. 7. (1789) ; Dec. Fl. Fr.2. 415. (1815) ; Agardh Aph. 104.(1822); Gre- 

 ville Flora Edin. xv. (1S24) ; Fee in Diet. Class. 8. 131. (1825.) 



Diagnosis. Flowerless terrestrial plants, with their sporules contained in 

 dehiscent thecae, destitute of an operculum. 



Anomalies; Riccia has indehiscent fruit immersed in the substance of the 

 frond. 



Essential Character. — Plants growing on the earth or trees in damp places, composed 

 entirely of cellular tissue, emitting - roots from their under-side, and consisting of an axis or 

 stem, which is either furnished with leaves, or leafless, and then bordered by a membranous 

 expansion; these expansions sometimes unite at their margins, so as to form a broad lobed 

 thallus. Reproductive organs of several kinds ; either a 1- 2- or 4-valved theca, supported 

 upon a membranous peduncle, covered when young by a leaf, through which it afterwards 

 protrudes, and often containing spiral fibres, called Elateres, within which the sporules are 

 intermixed; or a peltate stalked receptacle, bearing theca? on its under surface; or sessile 

 naked theca, either immersed or superficial. Besides these there are in Jungermannia " mi- 

 nute, spherical, membranous, reticulated bodies, supported upon short white peduncles." 

 {Grev.) ; in Marchantia, " peltate receptacles, plane on the upper surface, and having oblong 

 bodies imbedded in the disk ;" and also " little open cups, sessile on the upper surface, and 

 containing minute gteen bodies (gemma?) which have the power of producing new plants, 

 as well as the sporules ;" and in Anthoceros, " small cup-shaped receptacles, containing mi- 

 nute, spherical, pedunculated, reticulated bodies." 



Affinities. The structure of the reproductive organs of this order is so 

 exceedingly variable that no common character seems deducible from them ; 

 nor has it been found possible either to determine what analogy exists between 

 the organs, or even to decide what their respective functions are. What are 

 here called the thecee are considered to be the cases of the sporules, properly 

 so called, but the other bodies are of a more doubtful kind. Those who have 

 sought for stamens and pistils in Ciyptogamous plants have naturally taken 

 the imbedded oblong bodies of Marchantia, and the pedunculated reticulated 

 ones of Jungermannia, for anthers ] but Dr. Hooker, in his beautiful Mono- 

 graph of the latter genus, and also in his British Flora (p. 459.), is evidently 

 unsatisfied as to their nature. Dr. Greville, in the Flora Edinensis, the most 

 useful and original work upon British Cryptogamic plants that we yet possess, 

 is clearly in a similar state of uncertainty ; and Agardh admits nothing more 

 in them than a resemblance to staminiferous organs, adopting the opinion that 

 they are a particular form of gemmules. The bodies lying in the cup-shaped 

 receptacles of Anthoceros have been said to be anthers, but upon no good evi- 

 dence. In Jungermannia there is a third kind of reproductive matter, consist- 

 ing of heaped clusters of little amorphous bodies, growing from the surface of 

 the leaves, and called gemma?. 



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