Mr. R. Spruce on the Musci and Hepatice 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, growing 
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, 1 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 Hepatic, 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, Isothecitum Philippianum of the Central, 
and Bartramia stricta of the Eastern. 
Distribution of Musci and Hepatice 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. Its fruit has never yet been found, and even its flowers 
were unknown when it was figured in the ‘ Bryologia Europea.’ A few years 
ago, Mr. Sullivant 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 Bagnéres, 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 aremarkable 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. {t has, however, ample means of maintaining and spreading itself 
without the aid of seeds, 
