FIRST DIVISION OF FLAMS. 



199 



Peat consists of from sixty to ninety parts in 

 the hundred of inflammable matter, resembling 

 thus far the composition of coal: the residue is 

 earthy matter, derived from an admixture of the 

 soil in which it has been produced. Besides the 

 mosses already mentioned, several lichens, heaths, 

 rushes, and shrubs, and trees, enter into the for- 

 mation of peat. Not unfrequently large trunks 

 and roots of trees are found amid peat ; and, in- 

 deed, whole forests have gradually fallen down 

 and become converted into this substance. The 

 rapidity with which large accumulations of this 

 matter is foi-med, is also remarkable, considering 

 thegradual process of thepeculiarvegetation. We 

 learn from a paper in the Philosophical Trans- 

 actions, that in the year 1651, when the earl of 

 Cromarty was nineteen years old, in travelling 

 over the parish of Loclibrun he passed by a very 

 high hiU which rose in a gradual acclivity from 

 the sea. At less than half a mile up from the 

 sea there is a plain about half a mile in circum- 

 ference, and from it the hiU rises in a constant 

 steepness for more than a mile in ascent. This 

 little plain was at that time completely covered 

 with' a firm standing wood, which was so very 

 old, that not only the trees had no green leaves, 

 but the bark was quite thrown off, which the 

 old countrymen, who were with his lordship, 

 said was the universal manner in which fir woods 

 terminated, and that in twenty or thirty years 

 after, the trees would commonly cast themselves 

 up from the roots, and so lie in heaps till the 

 people cut and carried them away. About fif- 

 teen years afterwards, his lordship had occasion 

 to come the same way, and observed that there 

 was not a tree nor even a single root of all the 

 old wood remaining ; but instead of these, the 

 whole bounds where the wood had stood was 

 all over a flat green ground, covered with a plain 

 green moss. He was told tliat nobody had been 

 at the trouble to carry away the trees, but that, 

 being all overturned from their roots by the 

 winds, the moisture from the high grounds 

 stagnated among them, and they had in conse- 

 quence been covered over by the green moss. 

 The' place was so soft and spongy, that his lord- 

 ship in attempting to pass over, sunk up to the 

 shoulders. Before the year 1699, (in the space 

 of forty-eight years) the whole piece of ground 

 was converted into a moss, and the country 

 people were digging peats out of it. At first 

 they were soft and spongy, but gradually im- 

 proved to the ordinary quality of peat. Ex- 

 tensive accumulations of peat are found in 

 England, Ireland, and Scotland, and in many 

 parts of the north of Europe. They exist par- 

 tially in the southern countries of Europe, as 

 France, Spain, and Portugal; but disappear as 

 we approach towai'ds the ton-id zone. Peat moss, 

 from containing a large proportion of tannin, 

 ia found to possess high antiseptic qualities; 



from this cause entire trees, with their seeds, and 

 the bodies of animals, are frequently found at 

 considerable depths, and after having lain for 

 centuries, in a wonderful state of preservation. 



As food or medicine, no species of moss is 

 now employed, although formerly polytriclmm 

 commune, which is highly astringent, was used 

 as a stimulant. 



Much uncertainty still remains regarding the 

 fructiferous organs of the mosses; we shall here 

 only briefly allude to this subject, as we have 

 treated it under the general view of the reproduc- 

 tive organs of the cryptogamia. Their sporules 

 are inclosed in a kind of capsules named thecce, 

 which are supported upon a slender thread {seta, ) 

 and are at first enveloped in a kind of bag, which 

 bursts circularly in the middle, and of which the 

 lower part remaining at the base of the thread 

 is named the iiagirmla, while the upper part 

 which covers the top of the theca has received 

 the name of cah/ptra. The theca itself presents 

 internally a central axis named columella, and 

 opens by means of a circular operculum. The 

 circumference of the aperture of the theca is 

 named the peristome, and is distinguished into 

 internal and external. It may be furnished 

 with teeth or cilise, closed by membranes, or 

 entirely naked. Besides these organs, there are 

 others of a different kind. These are irregularly 

 oval and elongated bodies, supported upon a very 

 short pedicle, and accompanied by articulated 

 filaments. 



The authors who have admitted in mosses the 

 existence of flowers composed of the same organs 

 as those of phanerogamous plants, have differed 

 much respecting the functions of these organs, 

 and the name which ought to be given to them. 

 Thus Hedwig, whose labours have thrown so 

 much light upon the history of plants of this 

 family, considers mosses as furnished with male 

 flowers and female flowers. The ovidal and vesi- 

 cular bodies, intermingled with articulated fila- 

 ments, he considers as male flowers, of which 

 each is composed of a naked and pediculate grain 

 of pollen. The thecse, on the other hand, are 

 female flowers. Palsot de Beanvois considers 

 the theca as a hennaphrodite flower, of which 

 the central columella is the pistil, and the gran- 

 ules which surround it the pollen. He considers 

 what Hedwig calls male flowers as mere buds or 

 bulbils of a peculiar nature. Dillenius, on the 

 other hand, describes the theca as a male flower. 

 Hill sees in it a hermaphrodite flower, the semi- 

 nula of which are the ovules, and the ciliae of 

 the peristome are the stamina. 



The Lycopodiums are intermediate in their 

 general appearance between the mosses and tlie 

 ferns. They are furnished with a branched, 

 often spreading and creeping stem, and very 

 numerous small leaves. The organs of fructifi- 

 cation present two modifications. Sometiiuci 



