288 The Mosses and Hepatics of Denbighshire. 



interfere with the germination of the spores of mosses and 

 hepatics. The more delicate species of these cryptogams 

 suffer to the extent of becoming extinct under such conditions. 

 These atmospheric impurities, however, affect the vegetation 

 of the country to the west and north-west of Llangollen to a 

 less degree than to any portion to the east of the town, because 

 of the proximity of the latter to the Ruabon and Wrexham 

 manufacturing and more populous centres. Such bark-loving 

 species as Orthotrichum Lyellii, O. affine and 0. stramineum 

 occur very sparingly in the former localities. In the Wrexham 

 area Nant y Ffrith produces the following corticole species 

 in small quantities : — Ulota Bruchii, U. crispa, Lophocolea 

 heterophylla, Frullania tamarisci and F. dilatata. The purer 

 air of the higher altitude at which this ravine stands, the 

 shelter and protection due to its depth, as well as the greater 

 amount of humidity that prevails, tend to counteract to some 

 degree the unfavourable atmospheric conditions that cause 

 the deterioration of plant growth in the district. It may be 

 of interest to mention here that William Wilson, of Warrington, 

 in his Bryologica Britannica (1855) records Orthotrichum tenel- 

 lum for Gresford Vale. The conditions to-day do not favour 

 the occurrence of this beautiful little moss in that locality. 



The average rainfall in inches from 1880 to 1884 f° r the 

 following places in the district is as follows: — 



Ruaton (Wynnstay) . . . . . . 34*87 



Llangollen (Plas Beryn) . . . . . . 4472 



Wrexham (Pack Saddle Reservoir) . . 33*32 



(Cae Llwyd Reservoir) . . 43*Si 

 (Plas Power) . . . . 36-55 



(Brymbo) . . . . . . 33-62 



Rossett (Trevalyn Hall) . . . . 29-08 



Chirk (Cefn-y-Wern) . . . . . . 35*45 



The following list contains records of mosses gathered 

 in the county of Denbigh by the late Professor Barker, of 

 Buxton. These records were compiled from MS. belonging to 

 him. A list of Hepatics collected by the same bryologist in 

 the Llangollen district is also included. This collection was 

 examined by Mr. Ingham, secretary of the Moss Exchange Club, 

 who kindly sent the records to the writer. The following 

 excursions by Prof. Barker in the county are represented by 

 the figures 1-10. A number quoted after each species, therefore, 

 refers to the locality in which that species was collected by 

 Prof. Barker. For records not followed by a number the 

 author is responsible. 



(1) Near Colwyn Bay and Bettws y Coed (V.C. 50), August 

 and September, 1899. 



Mosses collected and noted in the neighbourhood of 

 Llangollen (V.C. 50), August I4th-29th, 1900 : — 



Naturalist, 



