MOSS HABITATS. 57 



subject to much variation. Still, it maybe known by the 

 contorted branches, the large stem-leaves, strongly fibrose, 

 by the leaf-cells being smaller than in the last and bordered 

 round by numerous minute pores, and by the stem having 

 only a single layer of cortical cells. Fruits July and August. 



S. intermedium approaches S. aciitifolium in its more 

 slender habit ; it grows in loose tufts, and is usually yellowish 

 green. The stem-leaves are acute, but have neither the 

 small pores nor fibres noticeable in many other species. The 

 branch-leaves are acute and are somewhat undulated and 

 recurved at the points when dry. The fruit is found about 

 July or August. 



The foregoing characters cannot be considered as more 

 than vague guides by which to determine these plants, nor 

 do I know of any simple guide to a knowledge of the species 

 in this group ; only frequent comparison and a constant use 

 of the microscope will enable the student to properly under- 

 stand that most protean group of mosses, the Sphagnums. 



Possibly, the most restricted in their range are the Alpine 

 mosses ; for, whilst we may find many of the lowland mosses 

 ascending to high elevations, there are other species that 

 we should look for in vain, except either in high latitudes 

 or on the summits of our loftiest mountains. These Alpine 

 mosses will be found to vary considerably with regard to 

 the species to be found in any given district, the nature of 

 the rock, whether siliceous, calcareous, or granite, determin- 

 ing, in some manner, the character of the flora \ possibly, 

 the granite rocks have the more characteristic flora. To 

 enumerate all the species of moss that are to be found in 

 these elevated regions would be tedious. I shall therefore 

 merely call attention to a few of the more special species, 

 feeling assured that the student who seeks these will be so 

 enamoured by the subject that he will scarcely neglect those 

 not here mentioned. 



Of Alpine species the following may be considered as 

 representative : viz. Andrecza nivalis, A. alptna, Dicranum 

 Starkii, Grimmia ovata, G. atrata, Rhachomitrium patens, 

 Amphoridium lapponicum, Oligotrichum hercynicum, Pogo- 



