PTERTGIUM.] 



LICHINEI. 



35 



at the circumference, subcoraUoideo-multifid or microphylline and 

 usually diffracto-glubulose in the centre, dark-olive or olive-brownish- 

 black, opaque ; laciuioc thin, plane, multifid, imbricately crowded, 

 obsoletely rugulose. Apothecia smaU, plane or slightly convex, 

 black ; spores ellipsoid, 3-septate, 0,015-20 mm. long, 0,0u6-8 mm. 

 thick; hvmenial gelatine deep blue with iodine. — Cromb. Grc- 

 villea, V. p. lOS ; Leight. Lich. Fl. ed. 3, p. 12. 



This is externally somewhat like Pannaria triseptata Nyl., but differs 

 in the absence of a hypothallus, and iu the laciuije beinor radiate at the 

 circumference and usually digitate at the apices ; the spores also are 

 somewhat smaller. In the only fertile British specimen seen the apo- 

 thecia are sparuigly present. 



Hab. On schistose rocks in alpine situations. — Disfr. Very local and 

 scarce amongst the S. Grampians, Scotland. — B. M. : Summit of Craig 

 Calliach. Perthshire. 



3. P. Lismorense Cromb. Grevillea, v. (1877) p. 108. — Thallus 

 thin, subfurfuraceous, thinly or obsoletely radiate, adnate, variously 

 confluent, blackish or olive-black. Apothecia small, thinly mar- 

 gined, black, dark within ; spores oviform, 1-septate, 0,010-0,011 

 mm. long, 0,005-0,006 mm. thick ; epithecium bluish-black : hypo- 

 thecium cellular, and (with the perithecium) violet-blackish ; hvme- 

 nial gelatine bluish, then dark-vellowish with iodine. — Xyl. Flora, 

 1877, p. 221 ; Leight. Lich. Fl. ed. 3, p. 12.— Brit. Ex.t: Cromb. 

 n. 101. 



The thallus spreads rather extensively, though not continuously, over 

 the substratum. In its younger state the radii are more discrete at the 

 circumference. It is allied to P. asperellum Nyl., from which it differs 

 in the thallus and the smaller spores. 



Hah. On calcareous rocks in maritime tracts. — Didr. Local and scarce 

 in the S.W. Highlands. — B. M. : Island of Lismore, Argyleshire. 



11. leptogidium: 



Nyl. Flora, 1873, p. 195 

 {cfr. Cromb. Grevillea, v. 

 p. 76). — -Thallus minute, 

 fruticulose, branched, 



somewhat fragile ; goni- 

 mia moniliform ; cortical 

 laj-er cellular, distinct. 

 Apothecia subbiatorine ; 

 spores Snse, ellipsoid, 

 simple, colourless ; hyme- 

 nial gelatine bluish with 

 iodine. Spermogones not 

 seen rightly developed. 



This genus, recently in- 

 stituted by Nylander, i.< 



Fig. 7. a 



Leptogidium deyidriscinn Jfyl. — a. Thalline 

 branch and branchlet, X 30. b. Transverse 

 section of a branch, X 200. c. Apex of a 

 bifurcate branchlet, showing the moniliform 

 chains of the gominia. X 200. d. Two 

 series of gonimia, X 350. 



D 



