THE NATURALIST 



FOR 1901. 



TOR TULA CERNUA: 



A MOSS NEW TO THE BRITISH FLORA. 



CHAS. P. HOBKIRK, F.L.S., 



Ilkley ; Ex-President of the Yorkshire Naturalists' U?iion. 



Mr. George Webster, of York, has the honour to be the 

 fortunate finder of this, the latest addition to the British Moss 

 Flora — Tortilla cernua (Hueb.) Lindb. (Desmatodon cernuus 

 Bry. Eur.). Mr. Webster met with it at the end of September 

 last, in the West Riding- of Yorkshire, in small quantity only, on 

 the mag-nesian limestone near Aberford. This moss is not 

 included in Wilson's ' Bryologia Britannica' (1855), nor in the 

 more recent ' British Moss-Flora ' of Dr. Braithwaite ; there- 

 fore, as far as we are aware, it is new to the British Isles. 



Schimper gives the time of its fruiting - on the Continent 

 (fruct. matur. ) as July and August, and Mueller, whose records 

 are mostly sub-Arctic, as towards the end of summer; so that 

 next season it should be looked for through the limestone 

 district, say eastwards from Aberford towards Church Fenton, 

 and northwards from Sherburn to Grimston Park and Tadcaster, 

 particularly in the old disused, damp, limestone quarries, such 

 as Jackdaw Crag - Quarry, near Stutton, and others which are 

 frequent in the narrow band of magnesian limestone which 

 extends from Shireoaks northwards, through Knottingley, Tad- 

 caster, Wetherby, Knaresborough, and Ripon to West Tan field. 

 When we consider that this species has such a wide range in 

 Europe, as well as in Canada and the United States, it seems 

 strange that it should so long have escaped the observation of 

 our British bryologists. It is really a very well-marked and 

 distinct species, and is easily distinguished from all its congeners. 

 Lindberg, in his 'Natural Arrangement of Mosses' (M SC. 

 Skand., 1879), places it in the family Tortulacccc, genus Tortula, 



