Roccella (roksela)

[NL. (A. P. de Candolle, 1805), an accom. form (based on ML. rocca, roc a, a rock) of It. or cell a, F. orseille, etc., orchil: see orchil, archil.] A genus of par meliaceous lichens of the tribe Usneei. The thallus is fruticulose or finally pendulous, alike on both sides, and cottony. The species are few and closely related, grow cartilaginous-coriaceous; the medullary layertid loosely ing especially in the warmer maritime regions of the earth, and furnishing the famous archil or orchil of dyers. R. tinct or i a and R. fuci form is, the best-known species, are the chief sources of the dye. See cut under archil; see also canary - mo , cape - weed, dyer's - mo , flat - orchil, litmus, Mauritius - weed. roccellic (rok-sel'ik), a. [ in Roccella tinct or i a. roc cell in (rok-sel'in), n. [ Rochelle salt. See salt1. roches moutonnées (rosh mö-to-nā'). [F.: roc he, rock (see roach2, rock1 ); moutonnée, fem. of moutonné, rounded like the back of a sheep: see mutton.] Scattered knobs of rock rounded and smoothed by glacial action: fancifully so called from their resemblance, as seen rising here and there or in groups above a surface, to a flock of sheep lying down: sometimes Englished as "sheep-backs." The surface of rock, instead of being jagged, rugged, or worn into rugged defiles, is even and rounded, often dome-shaped or spheroidal. Such surfaces were called Roches Moutonnées by De Sau ure. J. D. Forbes, Travels in the Alps, p. 53.