EVERNIA] USNEACEX: 161 
OrpverR XI. USNEACES. 
Thallus fruticose, elongate, filamentous or strap-shaped, 
branched, attached at the base, usually radiate in structure ; 
strengthening hyphe generally present. Algal cells Protococcus, 
within the inner cortex. Apothecia roundish, sessile or shortly 
stalked, marginate ; asci 1—8-spored ; spores colourless or rarely 
brown, simple or septate. Spermogones immersed ; sterigmata 
simple, sparingly septate, with acrogenous or pleurogenous 
spermatia. 
Distinguished by the generally upright or pendulous elongate 
thallus, with basal attachment. Transition stages between the 
foliaceous and fruticose types occur in the genus Hvernia, in which 
the structure is only subradiate and the thallus, though usually with 
a single penetrating foothold, may form secondary basal sheaths. 
Cerania (Thamnolia) is doubtfully included in the Order. The British 
genera are as follows :— 
Thallus strap-shaped, narrow or broad. 
Structure subdorsiventral, with under surface 
CIM OKENE COLOUG oes oe ds cota osn ow eee oaeee 40. Evernia. 
Structure radiate, alike on both surfaces ......... 41. Ramalina. 
Thallus filamentous. 
Medulla with central chondroid strand............ 42. Usnea. 
Medulla of loose arachnoid hyphe.................. 43. Alectoria. 
Thallus stalk-like. 
Fronds hollow, tapering upwards .................. 44. Cerania. 
40. EVERNIA Ach. Lich. Univ. p. 84 (1910). (PI. 40.) 
Thallus erect or pendulous or somewhat decumbent, strap- 
shaped, divided or repeatedly branched, rather soft and flaccid, 
attached by a basal sheath, occasionally by a few rhizine ; 
differently coloured above and below. Algal cells Protococcus. 
Structure subdorsiventral ; cortex on both surfaces of gelatinous 
cells; gonidia mostly confined to a layer below the upper surface. 
Apothecia lateral or almost terminal, with a thalline margin ; 
paraphyses stoutish, simple; spores 8 in the ascus, small, 
ellipsoid, simple. Spermogones lateral, immersed, with pleuro- 
genous straight acicular spermatia. 
1. E. prunastri Ach. Lich. Univ. p. 442 (1810).—Thallus at 
first ascending then more or less decumbent or pendulous, the 
fronds irregularly strap-shaped, wrinkled-lacunose or somewhat 
furrowed, greenish-grey above, white beneath, becoming brownish 
and concolorous in herbarium, repeatedly divided and branched, 
especially towards the apex, usually about 5-10 cm. long, 
frequently sorediate at the margins or on the wrinkles (K +s. 
CaCl-). Apothecia rare, on a short stout pedicel, chietly lateral, 
moderate in size, the disc reddish-brown, the margin inflexed ; 
spores 7-10 » long, 4°5-6 p thick.—S. F. Gray Nat. Arr. i. 
I, M 
