478 GRAPHIDINEA: [DIRINA 
A small family represented in the British Isles by a single genus 
and species. It is classified under Graphidinez on account both of 
thalline and apothecial characters, and is nearly allied to Roccellacex, 
as was pointed out by Crombie in Monogr. i. p. 491 (1894). 
Spores fusiform, 3-septate, colourless............ Dirina. 
DIRINA Fr. Syst, Orb. Veg. p. 244 (1825). (Pl. 69.) 
Thallus crustaceous, continuous or cracked. Apothecia 
discoid or somewhat irregular or elongate, subimmersed in the 
areole or superficial, with a distinct thalline margin; hypo- 
thecium thickish, black ; spores 8 in the ascus, elongate-fusiform, 
4—8-septate, colourless. 
A maritime genus of few species but of wide distribution in warm 
or subtropical regions. 
1. D. repanda Nyl. in Mém. Soc. Sci. Nat. Cherb. v. p. 116 
(1857).—Thallus determinate and subefligurate, thick, continuous 
or areolate, generally unequal and coarsely warted-granulate, 
greyish-white with a soft farinose surface and a white hypo- 
thallus (Kf + yellow, CaCl + rose-red). Apothecia moderate in 
size (up to 2 mm, across), at first closed then plane, black, 
covered generally with a white pruina, the thalline margin 
thick, obtuse, more or less inflexed ; hypothecium thick, black ; 
paraphyses simple, slightly widened or irregular upwards ; spores 
fusiform, often slightly bent, 3-septate, generally about 22 pw long, 
5 p thick, but sometimes smaller or larger ; hymenial gelatine 
wine-red with iodine.—Cromb. in Journ. Bot. ix. p. 178 (1871) 
& Monogr. i. p. 491, fig. 69; Leight. Lich. Fl. p. 235; ed. 3, 
p- 226. Parmelia repanda Fr. Lich. Eur. p. 177 (1831). 
Exsice. Johns. n. 421. 
A Mediterranean plant chiefly. The apothecia are often crowded 
and become difform, with the margin flexuose, Spermogones are 
abundant. 
Hab. On rocks in maritime districts.—Distr. Rare in the Channel 
Islands, 8.W. England and N. Wales.—b. M. La Coupe and Rozel, 
Jersey; Portland Island, Dorset; Great Orme’s Head, Carnarvon- 
shire. 
Orver XXI. ROCCELLACEA. (Part 2, p. 200.) 
Thallus mostly fruticose, of strap-shaped or rounded branching 
fronds, attached to the substratum by a basal sheath, corticate, 
with a central medulla generally of loosely interwoven hyphe. 
Algal cells Trentepohlia. Apothecia discoid or somewhat elon- 
gate, usually with proper and thalline margins ; spores 8 in the 
ascus, colourless or rarely brownish, elongate, septate. Spermo- 
gones with simple or sparingly branched sterigmata and straight 
or curved acrogenous spermatia, 
