BRITISH LICHENS

352 . PYRENOCARPElE ARTHOPYRENIA
elongat1lla Nyl. in Flora Ii. 164 (1868). V. punctiformis f.
elongatula Leight. Lich. Fl. 434; ed. 3, 466; Cromb. Lich. Brit.
120.
Not to be confused with A. liUbmicans, the spores of which are
4·guttulate but finally 3·septate. It differs from A. stigmatella, with
which it has been associated, in the greyer more superficial thallus,
in the narrower guttulate spores which are massed in the ascus and
in the presence of paraphyses. Nylander gives the size of the spores
at 36-50 (J. long, 7-10 (J. thick, but these measurements are not borne
out by an examination of Carroll's specimens.
Hab. On bark of trees.-Distr. Rare in S.W. Ireland.-B. M.
Dinish and Torc Mt., Killarney, Kerry; Loughcooter, Galway.
9. A. byssacea A. L. Sm.-Thallus filmy, whitish, thin, effuse.
Peri the cia minute, black, globose, semi-immersed; perithecial
wall curving inward, dimidiate; paraphyses numerous, branched,
free; asci elongate-clavate, about 70 !-tlong, 17 (J. wide; spores 8 in
the ascus, fusiform, I-septate( 1), colourless, 15 (J. long, 4 (J. thick.
- Verrucaria byssacea Tayl. in Mackay Fl. Rib. ii. 89 (1836) .(non
Ach. fide Leight. Angioc. Lich. 38).
Leighton suggests (t. c.) that Taylor's species is identical with
Acrocordta biformis, but the minute perithecia and the structure of
asci and spores are entirely distinct. There is only one small specimen
in the herbarium of the British Museum collected by Dr. Taylor; the
spores are somewhat imperfectly developed, but so far as can be
determined they are I.septate.
Hab. On barks of trees, oak and elm.-B. M. Presumably Kerry.
(Ex Herb. Salwey.)
Growing on trees,- thallus dark-coloured,- spores I-septate.
10. A. Laburni Arn. in Flora xliv. 537 (1861); Sydow Flecht.
Deutschl. 295 (1887).-Thallus thin, smooth, brown or brownishblack,
forming dark spots on the bark. Peri the cia minute,
hemispherical, semi-immersed, black and shining; perithecial
wall dimidiate; paraphyses indistinct, disappearing-; asci
rather swollen, narrower upwards; spores oblong-linear, I-septate,
scarcely constricted, the' cells almost equal, sometimes with two
or more guttulal; 20-25 (J. long, 4-5 (J. thick; hymenial gelatine
yellow with iodine.-A. FU'l11ago Mudd Man. 302 (1861) (non
Koerb. Syst. Lich. Germ. 370 (1855)). Verrucaria Laburni
Leight. Lich. Fl. 435 (1871); ed. 3, 465 ..
Exsicc. Leight. n. 254; Mudd n. 291.
Easily confused with A. rhyponta; it differs in the narrower,
2·celled spores.
Hab. On laburnum and other trees.-Distr. Rare throughout the
British Isles.-B. }rI. Near Whitestaunton, Somerset; Cirencester,
GIoucestershire; Ayton, Cleveland, Yorkshire; Trefriw, Carnarvon·
shire; Aberfeldy, Pcrthshire. •