222 LICHENES. [Borrera. 



greyish-brown bearing powdery warts, apothecia flat almost 

 black and pruinose with a scarcely prominent border. — Ach. 

 Syn. p. 2 43. — Lichen Boccella, Linn. — E. Bot. t. 211. — Dill. 

 Muse. t. 17. f. 39. 



Maritime rocks, in the extreme south of England. Guernsey, M. 

 Gosselin. Portland island, Lord Viscount Lewisham. Abundant on the 

 steep rocks of the Scilly islands, Hooker. — This interesting Lichen is the 

 famous Archill or Or chill ; Orseille of the French : which yields the most 

 valuable dye of all this tribe. Its several names are derived from a 

 Florentine family of the Oricellarii, Rucellarii, or Rucellai, one of whom, 

 fn the year 1300, carried on a considerable trade in the Levant, and, re- 

 turning with great wealth to Florence, first made known in Europe the 

 art of dyeing with this plant. Far more abundantly than with us, it is 

 a product of warm climates, on maritime rocks in almost every part of the 

 world and always growing mixed with the following species, which might 

 almost lead to the suspicion that they were varieties of each other. The 

 Canary islands formerly yielded this Lichen in abundance, whence it has 

 been called Canary weed ; but so great has been its consumption of late 

 years, that the best quality of it, whose average price is .£200 the ton, 

 has become extremely scarce : and what is commonly imported from 

 other countries is not worth £30 the ton. The English blue broad- 

 cloths me first dyed with Archill, which gives their peculiar lustre and 

 purple tint when viewed in a certain light. 



2. R. fuciformis, Be Cand. {flat-leaved Archil T); thallus flat 

 branched nearly upright greyish-white bearing powdery warts, 

 apothecia pruinose bordered. — Ach. Syn. p. 244 — Lichen fuci- 

 formis, Linn E. Bot. t. 728.— Dill. Muse. t. 23. /. 61. 



On maritime rocks, with the preceding : — from which it is distin- 

 guished by its much larger size, broader flat fronds, and paler colour. 

 Its quality too, as a dye, is greatly inferior to the preceding, as Mr. 

 Mackintosh assures me — The R. f)hycopsis of Ach. seems to be only a 

 variety of this, and almost intermediate between it and the preceding 

 species. 



28. Borrera. Ach. Borrera. 



Thallus cartilaginous, branched and laciniated, the segments 

 free, generally grooved beneath, the margins frequently ciliated. 

 Apothecia orbicular, peltate, beneath formed of the thallus ; the 

 disk coloured and surrounded by the elevated inflexed border 

 formed also of the thallus. — Named in compliment to W. Bor- 

 rer, Esq. by Acharius, who with great truth terms him " Liche- 

 nologus eximius." The species of which it is composed are 

 generally plants of a southern latitude. 



1. B. cilidris, Ach. (larger ciliated Borrera) ; thallus spreading 

 greyish-green minutely downy, the segments linear branched 

 ciliated especially towards the extremity, white and grooved be- 

 neath, apothecia elevated brownish-black and pruinose concave 



at length plane with a jagged border. — Ach. Syn.p. 22 Lichen 



ciliaris, Linn.—E. Bot. t. 1352 Dill. Muse. t. 20. /. 45. 



Trunks of trees, frequent. 



2. B. tenella, Ach. (lesser ciliated Borrera); thallus spread- 

 ing whitish-grey smooth, the segments linear subpinnatifid as- 



