BRITISH LICHENS

ARTHONIA ARTHONIACEJE 235
14. A. dcndritica A. L. Sm.-Thallus whitish or greyish,
effuse, tartareous, rather thick in places, smooth. Apothecia
black, innate, roundish or somewhat elongate and irregularly
radiate, contiguous and confluent or solitary, plane, internally
pale; asci pyriform; spores obovate, or clavate, colourless, 2-4septate,
upper cell largest, 17-22 {.I. long, 5-7 !J. thick.-Stigmatidium
dendntwum Leight. in Journ. Bot. xiIi. 257, t. 166 (1875) &
Lich. Fl. ed. 3, 413.
Exsicc. Larb. Lich. Rb. n. 192.
Resembles Enterographa in the character of the thallus, but is
separated from that genus by the character of the apothecia and by the
form and structure of asci and spores.
Hab. On rocks.-Distr. Very rare in W. Ireland.-B. JJf. Tully and
Doughruagh Mt., Connemara, Galway (the only localities).
15. A. ilicina Tayl. in Mackay Fl. Rib. ii. 105 (1836).­
Thallus cream-coloured, thin, smooth, shining, limited by a
brownish border varying in width. Apothecia small, scattered,
subimmersed, irregularly round or oblong, blackish-brown, plane;
spores colourless or pale yellow, obovate-clavate, 6-septate, the
upper cell largest, 21-36 {.I. long, 9-12 !J. thick; hymenial gelatine
blue, the asci yellowish or wine-red, with iodine.-Leight. In
Ann. Mag. Nat. Rist. ser. 2, xiii. 441, t. 8, f. 36 (1854) & Lich.
Fl. 401; ed. 3, 425; Mudd Man. 248; Cromb. Lich. Brit. 102.
A. ilicinella Nyl. in Flora 1.179 (1867); Carroll in Journ. Bot. v.
259 (1867); Cromb. l. c.; Leight. Lich. Fl. ll. c. A. subexcedens
Nyl. in Flora lxii. 221 (1879); Cromb. in Grcvillea viii. 29.
Exsicc. Cromb. n. 196; Larb. Lich. Rb. nos. 154, 277 (as
A. subexcedens).
Hab. On holly.-Distr. Rare in S. England and in S. and W.
lreland.-B. ]}f. Withiel, Cornwall; Ivybridge, Devon; New Forest,
Hants; Eridge Park, Essex; St. Leonard's Forest, Sussex; Glenbower
'Vood, Cork; near Derrycurrihy, Cromaglown, Eagle'S Nest, Cloghan
and Tore Mt., Killarney, Kerry; Ballynahinch, Lough Inagh and Kylemore,
Connemara, Galway.
Spores 3-5-septate, cells equal in size.
16. A. cascarillre Leight. Lich. Fl. 394 (1871); ed. 3, 418.­
Thallus pallid-glaucous, thin. Apothecia blackish, minute,
simple, plane, oblong, or linear-oblong or irregularly difform by
confluence; spores elongate, colourless, 4-5-septate, 18 fL long,
6 fL thlCk.-Comocarpon cascarillce Fee ESB. Crypt. 99, t. 15, f.
4 (1824) & Suppl. 94, t. 42, f. 3 (1837). Specimen not seen.
Hab. On bark.-Distr. Reported from Glencar, Kerry and Kylemore,
Connemara, Galway, though Leighton (ll. c..) questions the
ldentity of these plants. Those he examined had spores 3-septate,
wlth a large upper cell. Fee's figure represents 4.septate spores, the
cells equal in size. A specimen from Johnson marked A. cascarzllre does