246 CYCLOCARPINE | PHYSCIA 
margin subentire or crenulate; spores oblong, 15-20 yw long, 
8-11 p thick—Cromb. in Grevillea xv. p. 78 (1887). Ph. 
tribacoides Nyl. 1. c.; Cromb. in Grevillea iii. p. 22 (1874) & 
Monogr. i. p. 315; Leight. Lich. Fl. ed: 3, p. 140. Lecanora 
tribacia Ach. Lich. Univ. p. 415 (1810). Psoroma tribaciwm 
S. F. Gray Nat. Arr. i. p. 445 (1821).  Borrera czxsia var. 
tribacia Mudd Man. p. 107 (1861). 
Ph. tribacoides is similar to Ph. tribacia except in the reaction 
with potash ; both turn yellow in the cortex and soredia, but the 
former gives a somewhat stronger colour in the medulla. Apothecia 
are extremely rare; there are none present in any of our specimens ; 
the description of spores, etc., is taken from Crombie (Monogr. i. 
p. 315). 
Hab. On trees in maritime districts.—Distr. Local and rare in the 
Channel Islands and 8. England.—B. M. St. John’s and St. Martin’s, 
Jersey; near Penzance, Cornwall; Lymington, Hants. 
16. Ph. subdetersa Nyl. in Flora lxi. p. 344 (1878) (note).— 
Thallus spreading, formed of rather wide appressed lobes, pale 
greenish-brown, sparingly sorediate on the surface of the lobes, 
the soredia and medulla yellowish (medulla K + slightly yellow) ; 
beneath brown, rhizinose. Apothecia unknown. 
Distinguished by the colour of the medulla and soredia. Upper 
and lower cortices are plectenchymatous. 
Hab, Among mosses on rocks in subalpine regions.—Distr. Very 
rare in W. England and 8. Grampians, Scotland.—B. M. North Hill, 
Malvern, Worcestershire ; Ben Lawers, Perthshire. 
17. Ph. orbicularis Dalla Torre & Sarnth. Die Flechten 
Tirol, etc. p. 165 (1902).—Thallus spreading, closely appressed, 
cracked and almost crustaceous or laciniate, the lacinie narrow, 
often overlapping, spreading in all dire¢tions, suberenate or 
entire at the tips, dark- or greyish-brown ; beneath very black, 
with crowded short simple or branched rhizine (K—, CaCl—). 
Apothecia rather small, generally numerous, the disc blackish- 
brown, the margin prominent, entire; spores ellipsoid-oblong, 
15-25 p long, 8-12 p thick.—Ph. obscwra Nyl. in Act. Soc. Linn, 
Bord. sér. 3, i. p. 309 (1856). Cromb. Lich. Brit. p. 39 (inel. 
var. chloantha, excl. var. ulothrix) ; Leight. Lich. Fl. p. 148 pro 
parte, ed. 3, p. 136 pro parte (incl. var. chloantha). Lichen 
orbicularis Neck. Meth. Muse. p. 88 (1771). Z. obseurus Ehrh, 
Pl. Crypt n. 177 (1785) nomen nudum. — L, cyelostelis Ach, Lich. 
Suec. Prodr. p. 113 (1798); Engl. Bot. t. 1942. Parmelia 
cyclostelis Ach. Meth, Lich. p. 199 (1803); 8. F. Gray Nat. 
Arr, i. p. 444 pro parte; Hook. in Sm. Engl. Fl. v. p. 202 
pro parte. Borrera obscura Mudd Man. p. 109 (1861) pro parte. 
Exsicce. Larb, Lich. Hb. n. 252 & Lich. Cantab. n, 14. 
A dull-ecoloured plant with an orbicular or irregular outline, 
frequently sprinkled with sorediate-like dots, which seem to be 
