VOL. XVIII. (3) THE MOSSES OF GLOUCESTERSHIRE 259 



ToHula Vahliana. The two species of Sphcerocarpus and 

 several species of Riccia are abundant in cultivated fields on 

 the Sandstone. 



The Forest of Dean is composed of Coal Measures, sur- 

 rounded by the Carboniferous Limestone, and this by Old Red 

 Sandstone rocks. This district, together with the Silurian tract 

 of May Hill, is the only part of the County where Sphagnum is 

 found in any quantity, and with the Sphagnum are associated 

 many species of Mosses and Hepatics that are rare or absent 

 from other parts of the County. The Carboniferous Limestone 

 is present in the Bristol District as well as in the Forest of 

 Dean, and these rocks in the Avon Gorge near Bristol and in 

 the wooded valley of the River Wye afford a suitable habitat 

 for many rare species. Weisia calcarea, Trichostomum nitidum, 

 Eurhynchium circinatum and striatulum are found in both 

 valleys ; and Bryum provinciate, Anomodon longifolius, Thui- 

 dium recognitum, Orthothecium intricatum, and Amblystegium 

 compactum in the Wye Valley. Close to the Limestone in the 

 Forest of Dean are the conglomerate-beds of the Old Red 

 Sandstone. These rocks form a conspicuous feature at The 

 Buckstone, near Staunton, and also appear near Mitcheldean, 

 at Rodmore Grove, and at Abbott's Wood and Viney Hill, 

 near Blakeney. The following Mosses are, in this County, 

 confined to the Old Red Sandstone : — Cynodontium Bruntoni, 

 Dicranum fuscescens, D. Scottianum, D. montanum, Gnmmia 

 trichophylla, D. Hartmani, Orthotrichum rupestre, Hedwigia 

 ciliata, Schistostega osmundacea. 



In this list I have followed Dixon's " Handbook of British 

 Mosses " (2nd edition, 1904) for the names and arrangement of 

 the species. The number of species and subspecies for the 

 whole County is 304, and of these 234 are found in East 

 Gloucester, and 286 in W>st Gloucester. The larger number 

 of species in the West is accounted for by the greater variety 

 of the geological formations, which consist of a succession of 

 strata from the Silurian to the Jurassic, while the East is 

 composed almost entirely of the Jurassic. 



Unlike the Flowering-plants, there are very few mosses in 

 this County which are not truly native. Leptobryum pyri- 

 forme is an exception, as it is usually found only as a weed in 



