RAMALINA | USNEACEX 177 
Differs from the preceding in the position of the soralia and in the 
consequent short fronds. The anatomical structure is practically 
the same; the strong strands of strengthening hyphe sometimes 
meet, forming a bridge across the medulla. 
Hab. On rocks, in mountainous regions.—Distr. Local and scarce 
in N. England (?) and in the N. Grampians, Scotland.—B. M. Benna- 
boord, Aberdeenshire. 
42. USNEA Dill. Hist. Muse. p. 56 (1741) pro parte; 
Adans. Fam. Pl. ii. p. 7 (1763). (Pl. 42.) 
Thallus filamentous, upright or pendulous, generally cylin- 
drical, variously branched, often scabrid, greyish-green or 
yellowish, attached at the base by a sheath or by a penetrating 
holdfast ; structure radiate with a firm chondroid central axis, 
or very rarely hollow, the cortical layer thin. Algal cells 
Protococcus. Apothecia mostly rather large, lateral or terminal, 
peltate, the disc usually rather light-coloured with a thalline, 
generally ciliate margin; hypothecium colourless, with under- 
lying gonidia ; paraphyses concrete, branched and septate ; asci 
8-spored ; spores small, ellipsoid, simple. Spermogones lateral, 
immersed or slightly protuberant, light or dark coloured with 
sparingly branched sterigmata and acrogenous spermatia. 
Our species of Usnea occur chiefly on trees in forests, and the 
pendulous forms may attain a length of 1 ft. or more; occasionally 
they grow on rocks. Nearly all are sorediate, and in some species 
the soredia develop on the parent plant as lateral branchlets. Flesh- 
coloured tubercles—called pseudo-cephalodia—are frequently formed, 
and are irregularly scattered over the filaments. They are composed 
of dense hyphe which rise from the gonidial tissue; no gonidia are 
enclosed in these tubercles, which are only abortive apothecia. 
1. U. florida Web. in Wigg. Prim. FI. Hols. p. 91 (1780).— 
Thallus erect, one or several main stalks rising from the base, 
repeatedly forked, terete, about 1°5 mm. in diameter, finely 
verruculose, sometimes becoming bare and almost smooth, 
secondary branches more slender, patent, both primary and 
secondary generally beset all round with short or elongate 
horizontal fibrils, and frequently scabrid with soredia, pale- 
greyish or greyish-green. Apothecia plane, moderate in size or 
large up to about 1 cm. in diameter, geniculate or apparently 
terminal, the margins bordered with long slender cilia which are 
occasionally branched and sparsely fibrillose; spores shortly 
ellipsoid, 7-11 » long, 6—7 p» thick.—S. F. Gray Nat. Arr. i. 
p-. 403 (inel. var. rubiginea); Hook. Fl. Scot. ii. p. 70 & in Sm. 
Engl. Fl. v. p. 226; Cromb. in Journ. Linn. Soe. xvii. p. 555 
(1880); var. rubiginea Ach, Lich. Univ. p. 621 (1810)? U. ceratina 
var. scabrosa Ach. Lich. Univ. p. 620 (1810)? Cromb. in Journ. 
Bot. xx. p. 272 (1882) & Monogr. i. p. 206 pro parte (incl. 
f. ferruginascens Cromb. in Trans, Essex Field Club, iv. p. 60 
(1885) pro parte. U. barbata var. florida Fr. Lich. Eur. p. 18 
1. N 
