GEOGRAPHICAL DISTRIBUTION OF MOSSES. /// 



important is that of altitude or range above the sea level ; 

 this is marked out by lines or arches, extending from pole 

 to pole, the crown or highest point being at the equator, 

 and gradually descending northward, whilst at the Arctic 

 zone they become approximated. Professor Schimper has 

 described five zones of altitude, all of them characterized by 

 certain predominant species. 



Commencing at the sea level, we have ist. The Cam- 

 pestral region, or that of cereal plants and fruit trees, which 

 ascend the mountains to a varying height, according to the 

 latitude. Thus, in the southern zone, in the Pyrenees, it 

 reaches 3,100 feet on the south side, and 2,100 feet on the 

 north side. In the middle zone it approaches 1,400 feet 

 in the southern parts, falling to 750 feet and 500 feet in 

 the northern limits. In the northern zone so rapidly from 

 500 feet to o, that at 60 it disappears, and thus in the 

 Arctic part of this zone the campestral region is wanting. 

 This region in the separate zones presents different con- 

 ditions of surface, such as the artificial substratum of 

 elevated fields and roadsides, hills and woods, open desert 

 plains, heaths, bogs, and marshes, and all varying inter se^ 

 according to the nature of the soil, whether calcareous or 

 sandy, argillaceous or loamy, rocky or stony ; and as each 

 of these is more favoured by certain species, the aspects of 

 the campestral region are very varying. In this region are 

 found all those species which are diffused over the downs, 

 heaths, woodlands, and hills of moderate elevations in the 

 British Islands, a list too numerous to enumerate. 



2nd. The Mountain region ascends from the region of 

 cultivated plants to the upper limit of the beech, and 

 extends in the southern zone from an altitude of 5,800 feet 

 to 6,800 feet, in the middle zone from 1,400 feet to 3,400 

 feet, and in the Arctic northern descends into the plain 

 very little above the sea level. The features of surface are 

 dense woods of oak, beech, and pine, stony banks of 

 streams and rocks, all localities congenial to a rich growth 

 of mosses. The most characteristic species are Bryum 

 crudum, elongatum, Duvalii, Cindidium stygium, Ampho-^ 

 ridium Mougeottii, Racomitrium sudeticum, microcarpumi 



