Hub. On rocks in maritime ilistricts.- ~Distr. Very local tlioug-li pleii-
titul wliere it occurs, in the Channel Islands and S.AV. England.—IB. AI. ;
Alont Orgueil, Island of Jersey. Near Laud’s End aud Penzance, Cornwall ;
St. Alaiy’s, Scilly.
13. E. geniculata Hook. & Tayl. Loud. Journ. Bot. 1844, p. 055.
—Thallus moderate or somewhat small, subrounded or suboompressed,
smooth, or ohsoletely longitudinally subnervose, cæspitosely
and subfastigiately branched, pale or pale straw-coloured, often
terebrate with scattered perforations, fistulöse within ; branches
usually a tten u ate (medulla K—). Apotheoia small, term in al or sub-
terminal, pale-testaceous or glaucous-white, th e receptacle smooth
or rugulose ; spores oblong or fusiformi-oblong, stra ig h t (or obso-
letely slightly curved), 0,0 0 9 -0 ,0 1 5 mm. long, 0 ,0 0 4 -7 mm. thick.
■—Nyl. Bull. Soo. Linn. Normand, ser. 2, iv. p. 1 6 3 ; Cromb. Journ.
Bot. 1876, p. 360 ; Leight. Lich. El. cd. 3, p. 90.
Resembles R. gjusilla Ire Prév., a plant found in Portugal hut not
reaching our Islands ; it is distinguished by the cortical texture and the
sliinipg, smooth, and more freely divided thallus. To the following species
also it presents several points of alliance. I t is interesting as one of the
exotic plants which extend to AV. Ireland. In the British specimens the
apothecia, which are appendiculate, are very sparingly present.
Hah. On stems of shrubs (tliorns) iu maritime districts.—Distr. E x tremely
local_ and scarce iu N.AV. Ireland, though we may expect to find
it iu the S.AA . also.—B. AI. ; Killery Bay, Connemara, co. Galway.
14. R. minúscula Nyl. Bull. Soo. Linn. Normand, sér. 2, iv.
(1870) p. 164.—Thallus small, subrounded, shining, soft, subpel-
lucid, very finely longitudinally striatu late, cæspitosely branched,
straw-coloured or pale straw-coloured, branches atteniuito-ramulose
(medulla K - ) . Apothecia small, terminal, plane or convex, yellowish
flesh-coloured or glaucous, the receptacle smoothish beneath ;
spores oblong or fusiformi-oblong, stra ig h t, 0,009-0,015 mm. long!
0,004-6 mm. thick.—Cromb. Grevillea, vii. p. U 2 .— liam a lin a
calcaris f. minúscula Nyl. Sallsk. pro E. et Fl. Fenn. Forh n s v
(1866) p. 114. ■
1 his might be taken for a small, narrow state of R. fastigiata, or for a
young condition of R. calicaris. I t is, however, a very distinct species
dittermg from the preceding in the smaller and softer thallus, which ii
scarcely more than J inch in height ; it occasionally presents small scattered
oblong perforations. In British specimens tbe apothecia are very
Hab. On the branches of stunted larches, and erratic on rocks in
a wooded mountainous district.—Dfsri-. Verv local and scarce, found onlv
ainonu the As. Grampians, 8 co tlan d .-B . M. ; Craig Chmy, Braeinare
Aoerdeensliire, ’
Tribe X. U S N E E I Nyl. Mem. Soc. Cherb. iii. (1855) p. 170.
Thallus frutioulose, somewhat rounded, rarely angulose, erect or
pendulous, inte rn ally with a firm chondroid axis. Apothecia leoanorine,
qieltate, terminal or la te ra l ; spores 8nse, small, simple,
colourless; paraphyses no t discrete. Spermogones im m e rsed ; sterigmata
simple or suhsimple.
A natural tribe, distinguished from its allies hy having internally a
solid axis (as iu Stereocaulon), wliich readily separates from the cortical
layer. Comprising only three small genera, two of which, Neuropogon
and Chlorea, do not occur in Great Britain, it is with us, as in most other
countries, marked by the abundauce of the species of Usnea.
37. USNEA Hill. Muse. (1741) p. 56 qiro p a r te ; Ach. Aleth.
(1803) p. 306.—Thallus filamontoso-elongate, or tihrilloso-ramulose
w ith p a ten t branches, concolorous on both sides ; chondroid axis
composed of densely conglutinate fllaments, cortical layer fragile
and often diffract. Apothecia concolorous or suhconoolorous with
Fig. 40.
Usnea jlorida Aoh..—a. Longitudinal section of the thallus, X200. b. Vertical
section of a young apotbeciura (with thalline recejrtacle), x30. c. Theca and
paraphysis, X 350. d. Spores, X 500. e. Transveree section of tbe thallus,
showing above a spermogone (beneath whicli is a section of tbe medulla),
X30. f . Sterigmata and spermatia, X500.
th e thallus, often with ramuloso-ciliate margin ; hypothecium colourless
; spores small, ellipsoid ; paraphyses stipate in th e dense
hymenial gelatine, w'hich is bluish w ith iodine. Spermogones
lateral, slightly protuberant, in colourless conceptacles ; spermatia
stra ig h t, cylindrico-acicular, slightly incrassate towards the base.