1 86 The Flora of Glamorgan. 



not nearer to Swansea than Dunraven ! Gutch. Phyt. 1842. />. 183. 

 Fontigary ! very abundant ! and sparingly as far as Dunraven ! J.S. 

 By the wall on the Rhiw leading to the Kymin, Penarth. 16. 5. 1847. 

 J.E. The species originally ranged from Penarth to Dunraven, and 

 as it is often quite inaccessible it is not in danger of extermination. 

 Plants still grew at Barry in 1899 and at Dunraven in 1907. It is 

 strictly confined to the coast, and almost, though not quite, to the 

 peculiar habitat noticed by Llwyd over 200 years ago — wet rocks, 

 incrusted with a calcareous deposit, and provided with deep well- 

 sheltered pockets. It occurs, however, on the clays and shales 

 between the limestones in the immediate neighbourhood of such 

 spots, but only when protected by tufts of grass or other vegetation. 

 The critical factor governing its distribution appears to be that of 

 temperature — the water supply is probably of secondary importance. 

 Frost is rare on the coast, but nevertheless the winter cold regularly 

 destroys the leaves. The rhizomes are protected from extreme cold 

 by the water (weak springs), and in exceptional seasons, perhaps by 

 a covering of ice. Measurements of the temperature of this water 

 and of the solid substratum, observations on the freezing of the 

 water and laboratory experiments on the effects of low temperatures 

 on this species would be of great value, and give much-needed 

 information as to the critical factors which limit the distribution 

 of such a species. 



Pteris, Linn. 517. 



1866. aquilina, Linn, Bracken. Adain-redynen eryraidd. 

 Common. Abundant. Native. Ericetal, sylvestral, etc. 



It is worthy of note that the bracken with us occurs in great 

 abundance on the fixed sand dunes, being often the dominant species. 

 Massart. in his studies of the Belgian flora, describes it as calcifuge, 

 absent from the dunes, or rare there. The difference in rainfall or 

 atmospheric humidity probably accounts for its different behaviour 

 in these two areas. As this fern is a cosmopolitan plant — perhaps 

 the most widely distributed of all ferns — it must possess great powers 

 of adaptation. 



Cryptogramme, R.Br. 518. 



1867. crispa, R.Br. Parsley Fern. Adain-redynen y chwarelau. 

 Local. Scarce. Native. Rupestral. 



Mountain above Aberdare ; rare. J.S. Ferndale, very rare. 

 Fl. Rhondda. Padell-y Bwlch ; Daren Bwllfa. Ridd. Mardy. 

 Mr. Walker. Aberdare. Ed. Young. Ferns of Wales. Mynydd 

 Mayo, near Abertridwr. J.S. (2), T.H.T. and V. Graig fawr, 

 Cwm Pare. I 14-8-98. Craig-y-llyn ! 1905. U.C. Hb. Always, 

 I believe, on the screes of the Pennant Grit. Ed. 



Lomaria, Willd. 519. 



1868. Spicant, Desv. Hard Fern. Rhedyn Gwib. 

 Common. x\bundant. Native. Ericetal, sylvestral, etc. 



