64 COLLEMACEI. [LEPTOGITTM. 



1. L. rhyparodes Nyl. Flora, 1865, p. 210. Thallus diffuse, 

 thin, furfuraceous or subgrauulato-unequal, diffract, brownish-red 

 or blackish- brown (I + wine-red). Apothecia small, at first, con- 

 cave, becoming somewhat plane and at length biatorine with ex- 

 cluded margin, concolorous or reddish ; spores ovoid or ellipsoid, 

 attenuate at one or the other apex, submurali-divided, 0,020-35 

 mm. long, 0,011-16 mm. thick. Carroll, Journ. Bot. 1865, p. 287 ; 

 Cromb. Lich. Brit. p. 7 ; Leight. Lich. Fl. p. 35, ed. 3, p. 26. 

 CoUemapsarelhim Nyl. Flora, J 805, p. 602; Cromb. Journ. Bot. 1866, 

 p. 22 ; Lich. Brit. p. 3 ; Leight. Lich. Fl. p. 26 : vide Cromb. Journ. 

 Bot. 1874, p. 335. 



The thallus, which has the gonimia more or less scattered, sometimes 

 spreads extensively, and occasionally becomes almost evanescent. The 

 apothecia are at "first urceolate and sometimes at length subbiatorine. 

 Occasionally specimens growing on moist shady rocks are more obscure 

 and less developed with nearly biatorine apothecia ; this state is 

 Collema psorellum Nyl. 



Hab. On damp rocks and stones (schistose) in subalpine and alpine 

 -ocalities. Distr. Very local and rare among the S. Grampians, Scot- 

 and. B. M. : Craig Calliach, on the summit and above Loch-na-Gat, 

 Ben Lawers, Perthshire. 



2. L. tenuissimum Koerb. Syst. Lich. Germ. (1855) p. 419. 

 Thallus effuse, squamuloso-granulose, olive- or brownish-green ; 

 squamules laciniato-dissect or crenato-incised, congested into a dense 

 crust. Apothecia moderate or large, urceolate, reddish-brown, the 

 margin entire, thick, paler ; spores ovoid or oblong, narrower at 

 either apex, irregularly murali-locular, 0,024-34 mm. long, 0,011- 

 13 mm. broad. Mudd, Man. p. 46 ; Cromb. Lich. Brit. p. 7 ; Leight. 

 Lich. Fl. p. 35, ed. 3, p. 26. Collema tenuissimum Sm. Eng. Fl. v. 

 p. 213. Polychidium tenuissimum Gray, Nat. Arr. i. p. 401. Lichen 

 tenuissimus Dicks. Crypt, fasc. i. (1785) t. 2. f. 8 ; With. Arr. ed. 3, 

 iv. p. 61 ; Eng. Bot. t. 1427. Brit. Exs. : Mudd, n. 4. 



Well distinguished by the external character of the thallus from the 

 allied species of the subgenus, and by the internal structure from states 

 of L. lacerum var. pulvinatum, which it resembles. The apothecia, 

 usually sparingly present, have the margin sometimes slightly connivent, 

 and are often comparatively large and deeply urceolate. 



Hab. On the ground among mosses and short grass in maritime and 

 upland districts. Distr. Sparingly here and there throughout England, 

 very rare in Scotland and Ireland. B. M. : Near Norwich, Yarmouth, 

 Norfolk ; Reigate Hill, Surrey ; Hastings and Twineliam, Sussex ; San- 

 down, Isle of Wight ; near Penzance, Cornwall ; Snowdon, Carnarvon ; 

 near Easby, Cleveland, Yorkshire. New Galloway, Kirkcudbrightshire ; 

 near Cramond, Edinburgh ; Appin, Argyleshire ; Ben Lawers, Perthshire. 

 Middleton, co. Cork. 



3. L. humosum Nyl. Mem. Soc. Cherb. v. (1857) p. 90 ; Syn. i. 

 (1858) p. 119. Thallus effuse, thinnish, consisting of lobulate gra- 

 nules closely aggregate (with larger lobules here and there inter- 

 mixed), brown or brownish-black. Apothecia small, somewhat 



