Mr. R. Spruce on the Musci and Hepaticee of the Pyrenees. 95 



explanation of this is to be found in what is above remarked re- 

 specting the depth of the valleys and the extent and density of 

 the forests ; pleurocarpous mosses demanding in the latitude of 

 the Pyrenees a great deal of shade. 



A few species, occurring in both the Central and Eastern 

 Pyrenees, were not observed in the Western. They are : — 



Hypnum reflexum. Desmatodon nervosus. 



Mielichoferia nitida. Dicranum longifolium. 

 Bryum polymorphum var. cur- virens. 



visetum. Grimmia atrata. 



Timmia megapolitana. Cinclidotus aquaticus. 

 Trichostomum tophaceum. 



The list of species wanting to the Eastern Pyrenees, but ob- 

 served in both the Western and Central, is so very large that I 

 forbear to insert it, feeling assured that when the former district 

 comes to be explored as the two latter have been, it will be found 

 much less deficient than this list would show it. Three mosses, 

 Amblyodon dealbatus, Tortula marginata and cuneifolia, gi'owing 

 in both the Eastern and Western Pyrenees, have not hitherto been 

 observed in the intermediate district. 



Were I now asked to name a moss characteristic of the whole 

 Pyrenees^ I should say at once Fissidens grandifrons, Brid. (the 

 Dicranum palmiforme of Ramond), which is a conspicuous orna- 

 ment wherever moist calcareous rocks are found, but is scarcely 

 met with out of the Pyrenees*. Amongst the Hepaticse, Jun- 

 germannia acuta is scarcely less abundant, growing on the same 

 sort of rock. The following species may also be considered re- 

 spectively characteristic of our three districts, viz. Southbya 

 tophacea of the Western, Isothecium Philippianum of the Central, 

 and Bartramia stricta of the Eastern. 



Distribution of Musci and Hepaticce in the Pyrenees, according 

 to altitude. — We come next to treat of the vertical distribution 

 of plants, the most interesting branch of Phytostatics. In at- 

 tempting to define our zones of altitude by natural boundaries, 



* It will not be out of place to mention here a curious circumstance re- 

 lating to this moss. \\.^ fruit has never yet been found, and even \U flowers 

 were unknown when it was figured in the * Bryologia Europsea.' A few years 

 ago, Mr. SuUivant discovered female plants at the Falls of Niagara, and in 

 1846 he published the specimens in his beautiful 'Musci Alleghanienses ' 

 (no. 186). In Jan. 1846, a single tuft of male plants was found by myself 

 and M. Philippe on a dripping limestone rock near Bagneres, and the in- 

 florescence will be described in the proper place. These are all the flowers 

 that have ever been found, and it will be a remarkable circumstance if it be 

 ascertained (as this would seem to show) that only the male plant exists in 

 Europe, and only the female in America\ The obvious conclusion would be 

 that the plant never had fruited, and without artificial aid never would 

 fruit. It has, however, ample means of maintaining and spreading itself 

 without the aid of seeds. 



