82 CRYPTOGAMIA LICHENES. 



at first, becoming nearly plane, with a flexuose granular 

 border. The inferior edges of the segments are brown. 



7. P. conspersa, imbricated, mountain-green ; segments of the 

 circumference radiating, cut and crenate, the centre roughened ; 

 under surface black ; apothecia chestnut-brown, with an even bor- 

 der. HOOK. Scot. ii. 55. Lichen centrifugus, LIGHTF. Scot. 814. 

 WITH. iv. 35. DILL. Muse. t. 24. f. 75. 



Hob. Rocks, not common in Berwickshire. On rocks by 

 the side of the Whiteadder about the Retreat, abundant. 



DILLENIUS, who gathered his specimens in Wales, was the 

 first to describe this lichen as a British species, in his 

 great work the Historia Muscorum. The frond forms 

 circular patches of a considerable size, and of a pleasant 

 colour, variously described as whitish-green, or greenish or 

 greyish-yellow, but which approaches nearest to what Mr 

 SYME calls mountain-green. The outer segments are 

 closely appressed and radiating, but the centre of the 

 circle often consists only of minute furfuraceous leaves, 

 which decay first and are worn away, leaving those of 

 the circumference in the form of a broad circular band. 

 The apothecia are numerous, crowded towards the middle, 

 saucer-like, rather large, the margin of the same colour as 

 the frond, thinnish, and generally waved. 



8. P. omphalodes, imbricated, purplish-brown, glazed, with white 

 zigzag cracks ; segments many-lobed, lobes plane, truncate, entire ; 

 beneath black, hirsute ; shields dark chestnut. HOOK. Scot. ii. 53. 

 Lichen omphalodes, LIGHTF. Scot. 818. WITH. iv. 36. WALKER'S 

 Essays, 191. Eng. Sot. t. 604. DILL. Muse. t. 24. f. 80. 



Hab. On stones on our higher moors. 



We are told by some of the older botanists, that the poor in 

 the counties of Derby and Lancaster, and in Wales, were 

 wont to dye their woollen clothes of a dull brown colour 

 with this lichen, but the colour was not durable. The High- 

 landers, and the people of the Western Islands of Scotland, 

 to whom it is known by the name of Crostil or Crotal, 

 used it much for the same purpose ; but they appear to 

 have obtained a better colour by steeping the lichen in 

 urine till it became soft and like a paste, which they form- 

 ed into cakes, dried them in the sun, and preserved for use. 

 The country people in Ireland adopted a similar custom, 

 which, like all other customs of the kind, has probably now 



