256 Rev. P. Keith on the External Structure 



of his predecessors, but did nothing to elucidate the subject; 

 while Hill, by sowing the powder of" the little capsules, ob- 

 tained as the result of his experiment a crop of young mosses. 

 Finally, Hedwig, born, as it was said, to abolish cryptogamy, 

 perceiving the disorder and obscurity in which everything 

 lay relative to the fructification of the mosses, undertook the 

 arduous but indispensable task of investigating everything 

 ab initio^ and ultimately arrived at the conclusion, that the 

 mosses are universally furnished with everything necessary 

 to the botanical notion of a flower, and that their flowers are 

 chiefly dioecious, partly monoecious, and partly hermaphro- 

 dite. 



According to Heel wig, the barren flowers are the stars, disks, 

 or buds that terminate the branches and nestle in the bosom 

 of the leaves. In their exterior they consist of leaves or scales, 

 larger or more elegant than the other leaves of the plant, but 

 never terminating in hairs. These Hedwig regards as consti- 

 tuting the calyx. In the interior they consist of a number of 

 small thread-shaped and succulent substances, issuing from 

 between the leaves, or occupying the centre. These he re- 

 gards as stamens, furnished with an anther that bursts open 

 when ripe and discharges a pollen*. The fertile flowers are 

 of a most singularly curious construction. They consist of 

 an urn-shaped capsule surmounted with a calyptra or veil, in 

 the form of an extinguisher, and invested, at the base, with a 

 membrane called a perichectium or fence. Some writers have 

 called the fence a calyx, and the veil a corolla; but we be- 

 lieve there is no unanimity among botanists on this point. 

 The urn is sessile as in Phascum muticum, or surmounted on 

 a pedicle as in Polytrichum commune. When the veil falls, or 

 is forcibly torn off", its mouth appears, covered with a lid or 

 operculum; and when the lid falls, the mouth is found to be 

 furnished with a circular row of fine and tooth-like substances 

 called the peristomium or fringe. Within the urn, and in the 

 direction of its longitudinal axis, there is situated a slender 

 and cylindrical substance called the column. Its summit, 

 which overtops the urn, Hedwig regards as the style, and the 

 urn itself as the seed-vessel, which, when ripe, is found to con- 

 tain a multitude of spherical granules, from the sowing of 

 which Hedwig obtained a crop of young mossesf. Hence if 

 Hedwig's theory should be even erroneous, as it is thought by 

 many to be, it establishes at least one fact, namely, that the 

 granules of the urn or column are capable of reproducing the 

 species. 



The Hepaticcc, or Lfaerxwrts. — The liverworts are a tribe 



* Fund. Hist. Nat. Muse. chap. ix. -f Ibid. chap. x. 



