306 HYPNUM (bKACHYTHECIUM) SALEBROSUM as a BRITISH MOSS. 



If Mr. Davies could find iio Hypnum aureum at Lake Espingo, 

 he found there H. saJcbrosiun, which no one hut himself, so far as I 

 know, has ever seen growing so high up on the Pyrenees. I 

 gathered ahundant specimens in the central Pyrenees, but always 

 in temperate valleys, ■ in woods of beech and fir (Pimis Abies) — 

 never once above the upper limit of the latter, or within the zone 

 of Finns sijlvestris. Lieutenant Eenauld, a most accurate bryologist, 

 who is at present stationed at Tarbes, at the foot of the central 

 Pyrenees, and is doing excellent work in those mountains, the 

 results of which are consigned to the pages of the ' Pievue Bryo- 

 logique,' says (apropos of Brachythecium sahhrosiun and its sub- 

 species Mildeanum), " Brack. Mildeanum, Sch. Spi., ed. i. = Brack, 

 salcbrusum, var. j^idiistre, ejusd. ed. ii., is abundant, well-grown, and 

 fertile on moist grassy slopes, on clayey alluvium, at Semeac, near 

 Tarbes (alt. 350m.) .... It is not uncommon in similar sites 

 all along the sub-Pyrenean plateau [at from 300 to 540 metres 

 above the sea level.] Brack, salebrusiim, on the contrary, flourishes 

 most in fir- woods of the P;)T.'enees, where it grows on rotting 

 trunks and vegetable humus. Spruce does not indicate Br. sale- 

 broswn at all in the plain, but comprises it in his upper montose 

 zone [zona montosa jyars superior), corresponding to the region of the 

 Finns Abies, which quite agrees with my ^Dersonal observations." 

 (Piev. Bryol., 1878, p. 73). Observe, I do not assert that this 

 moss may not occasionally stray beyond its normal upper limit. I 

 have had some experience of the capacity of mosses for climbing 

 mountains — a feat far less easy of explanation than their descend- 

 ing along the course of streams. In the Pyrenees I have tracked 

 Hypnum moUuscuin through every zone of altitude, from the plain 

 up to the limit of eternal snow. In the first zone above the plain 

 it is copiously fertile; in the upper alpine zones utterly sterile. 

 Some grasses show a similar adaptability to enduring extremes of 

 climate. The herbage around and above Lake Espingo is largely 

 composed of Nardus stricta — a grass common also in the marshes 

 of the Landes, barely above the sea-level. 



Hypnum salebrosum grows, very si)aringly, in the valley of the 

 Yorkshhe Derwent, in two woods a mile apart, viz., the wood by 

 Castle Howard station and that opposite Kirkham Abbey, where I 

 first found it in November, 1846, growing on the trunks of trees at 

 a few feet from the ground. It was in fine fruit, and as I was then 

 fresh from gathering H. salebrosum in the Pyrenees, I at once 

 recognised it. In July, 1872, Professor Lindberg re-found it there, 

 not on a tree, but on a decaying post. It was then out of season, 

 but we satisfied ourselves it w\as the true plant. 



In 1847-8, when I was drawing up my account of the mosses 

 of the Pyrenees, I wished to cite a good figure of Hypnum salebrosum. 

 The figure under that name in ' Muscologia Britannica ' was 

 plainly the dioicous H. glareosum, but there was a beautiful figure 

 in Greville's ' Scottish Crj^Dt. Flora,' t. 284, which seemed true 

 H. salebrosum. Yvv greater surety I sent specimens of the two 

 species to Dr. Greville, and asked him to say to which of them his 

 figure really belonged. In reply he sent me for examination the 



