BRITISH LICHENS

PHlEOGRAPHIS GRAPHlDACElE 277
thin margins, the thallus forming a white pseudo margin ; perithecial
wall contmuous as a dark line under the base; paraphyses
closely conglutinate, inspersed with small granules, slightly
swollen and brown at the tips; spores elongate, colourless, then
brown, 7-8-septate, 42-48 {1. long, 9-12 {1. thick.---Opegrapha
dendr1tica Ach. Meth. 31, t. 1, f. 10 (1803); Engl. Bot. t. 1756;
Hook. in Sm. Engl. Fl. v. 147; Tayl. in Mackay Fl. Hib. ii. 106.
Graphis dendritica Ach. Lich. Univ. 271 (1810). S. F. Gray Nat.
Arr. i. 503; Mudd Man. 241; Cromb. Lich. Brit. 97; Leight.
Lich. Fl. 367; ed. 3, 431 (incl. fl. Smithii and acuta). Hymenoclecton
dendr1twum Leight. in Ann. Mag. Nat. Rist. ser. 2, xiIi.
387, t. 7, f. 23 (1854) (inc!. vars. Smtthii & acuta).
Exsicc. Larb. Lich. Coosar. n. 41; Carroll Lich. Rib. n. 11.
Well differentiated by the whitish well· developed thallus and tho
dendroid branchmg of the lirellre. Among the forms distinguished by
Leighton, f. Sm2thii is marked by the more deeply.immersed apothecll1
whICh branch at an obtuse angle, in this respect differmg from f. acula
in which the angle is acute. Usually the carbonaceous waJI is thinly
developed at the base of the apothecium, but in some forms it is thicker,
and occasionally there is a gap, observable in section with the mICro·
scope, causing the apotheeium to appear semidimidiate.
lIab. On trees.-Distr. In wooded regions, chiefly in S. England
and S. Ireland.-B. M. Guernscy; Rozel, Jersey; Hustyn Wood,
Bodmin, Cornwall; Carisbrookc, and near Shanklin, I. of Wight;
Totnes, Torquay, near Becky Falls, Ivy BrIdge and UIIacombe, Devon;
Southton Common, Som('rset; Stoney Cross, near Bartley Lodge,
Brockenhurst, and near Lyndhurst, New Forest, Hants; Minety,
Wilts; Ardingly, St. Leonard's, TunbrIdge Wells, Tilgate, Danny,
Charlton, near BrIghton, and Buckhurst Park, Sussex; near Penshurst,
Kent; Shere, Surrey; Llttle Waltham, Pod's Wood, Messmg and
Epping Forest, Essex; Craigforda, Shropshile; ncar Malvern, Wor·
cestcrshire; near Dolgelly, Merioneth; Castle Bernard Park, Bandon,
lUverstown and Rostellan, Cork; KIllarney, Kerry.
Form obtusa A. L. Sm.-Apothecia rounded and obtuse at
the ends, frequently furcate or sparingly branched, almost
superficial, the thalloidal margin almost disappearing.-Hymenodecton
dendriticum var. obtusa Leight. tom. cit. 388. Graphis
dendntwa f. obtusa Leight. Lich. Fl. 368; ed. 3, 43l.
A distinctlve form owing to the rather crowded and short blunt
superfiCIal lircllre. Leighton notes branchmg at an obtuse angle as
characterIstIC, but the branches form qUlte as frequently a right angle
with the main apothecium.
Ilab. On trees.-Distr. Rather rare, but coextensive with tho
species.-B. M. Torquay and near I1sington, Devon; New Forest,
Bants; Kemble, Wilts; Castle Bernard, Cork; Cromaglown, Killarney,
Kerry.
3. Ph. Lyellii A. Zahlbr. in Engler & Prantl Pflanzenf. i. 1*,
99 (1905).-Thallus thin, membranaceous, smooth, pale-olive
or rather dark (K + yellowish or yellow then red). Apothecia