BRITISH LICHENS

LITHOGRAPHA GRAPHIDACE.iE 245
simple the plant has ,cry much the external aspect of a Hysterium.
Zahlbruckner 1. c. considers that species wIth many· spored asC! should
be classified under Biatorella.
Hab. On the trunks of old trees in maritime and upland tracts.­
Distr. Rathcr local and scarce in S. and S. W. England.-B. M. Colrinick
Park, Cornwall; near Sidmouth, Cockmgton, near Torquay and the
Dart, Devon; Swanage, Dorset; WhItefield, I. of Wight; New Forest,
Rants.
5. L. petrrea Nyl. in Act. Soc. Linn. Bord. ser. 3, i. 393
(1856).-Thallus obsolete. Apothecia linear, simple, black,
slightly shining, gregarious, often somewhat flexuose; margins
tumid; disc narrow; hypothecium thick, black; paraphyses
very slender, somewhat branched; ascus many-spored; spores
very minute, 3-4 ,_. long, 1 ,_. thick; hymemal gelatine palebluish,
then. wine-red with iodine.-Cromb. Lich. Brit. 95;
Leight. Lich. Fl. 360; ed. 3, 393. Opegrapha petraJu Dur. Expl.
Sci. Alger. 278 (1846) (excl. syn.) (non Ach.).
Exsicc. Larb. Cresar. n. 40.
Not to be confounded wIth Bwtorella simplex, to states of which
it bears consIderable resemblance, but differs in the lirelliform, congregate
apothecia and the black hypothecium. The thallus is indicated
merely by a rudImentary dark hypo thallus.
Hab. On rocks, in maritime dlstricts.-Di61r. Found only in tho
Channel Islands and W. Ireland; no doubt to be detected elsewhere.
-B. M. Le Fret, Noirmont and La Moye, Jersey; near Kylemol'e and
Lettel'more, Galway.
90. XYLOGRAPHA Fr. Summa Veg. Scand. 372 (1849) pro
parte; Nyl. in Mem. Soc. Sci. Nat. Cherb. iii. 187 (1855); Massee
Fungus-Flora iv. 64 (as fungus). (Stletis § Xylographa Fr. Syst.
1\1yc. ii. 197 (1823) emend.) (Pl. 24.)
Thallus developed under the bark (hypophlreodal). Algal
cells Palmella. Apothecia innate or erumpent, lirelliform, not
carbonaceous, roundish-oblong or irregular; the disc plane or
concave; hypothecium usually pale; paraphyses slender; spores
8 in the ascus, simple, colourless; spermogones with simple
sterigmata and acicular curved spermatia.
Differs from Lithor;rapha in the plane or concave apothecia and in
the colourless or pale hypothecium.
1. X. parallela Fr. Summa Vcg. Scand. 372 (1849).-Thallus
forming elongate whitish spots or httle visible (Ie -, CaCl-).
Apothecia innate, erumpent, black, narrowly linear, straight,
developed in parallel rows, at first concave with slightly elevated
margin, becoming plane and immarginate; hypothecium colourless;
paraphyses discrete, brownish at the apices; spores ellipsoid,
11-16 fJ. long, 5-7 fJ. thick; hymenial gelatine bluish then vlOletcoloured
with iodine.-Cromb. Lich. Brit. 95; Leight. Lich. Fl.