PLACODIUM. 



and broken, and finally waited; brownish-ash-coloured ; con- 

 ditioned more or less in colour and bordered by a black hypo- 

 thallus; apothecia of middling size and smallish, biatorine, 

 sessile ; the flattish, rufous, white-pruinose disk surpassing at 

 length the obtuse, white, entire or finally fuscescent and flexu- 

 ous proper margin, which is rarely surrounded by an obscure 



thalline one. Spores ellipsoid, ^ mic. Lecanora, Obs. Lich. 



2, 1. c. p. 403. Placodium, ibid., 3, I c. p. 287. 



Trees and rails from southern Pennsylvania and Maryland 

 throughout Virginia, Tuckerman I. c. 1862. Massachusetts, on 

 Beech, Willey. Ohio, Miss Biddlecome. Illinois, Hall. North 

 Carolina, Curtis. South Carolina and Georgia, Eavenel. Texas, 

 Wright. Oregon, Hall. A well marked lichen; but states of 

 it may be passed over for Lecanora subfusca ; or now for forms 

 of the variable Biatora rubella. 



23. P. Floridanum, Tuckerm. ; thallus thin, contiguous, un- 

 even at length broken ; glaucous-cinerascent, limited more or less 

 and otherwise conditioned by a black hypothallus ; apothecia 

 minute, adnate; disk flat, brownish-black, opake, obsoletely 

 margiuate, with an entire, at length concolorous thalline border. 



Spores ellipsoid, ^ mi c. Lecanora, Obs. Lich. 2, 1. c. p. 402. 



Placodium, ibid., 3, I. c. p. 287. 



On bark, West Florida (Beaumont], and Texas (Wright), 



Tuckerman I. c. 1862. Also in the island of Cuba, Wright. 



Resembling small states of Einodina sophodes. 



f f Spores with approximate spore-cells (not polar -bilocular), 

 for the most part numerous in the thekes. Thallus now stalked, 

 now effigurate, and now uniform. 



24. P. Spraguei; thallus effuse, made up of short trunks 

 which are crowded together into a papillate crust, expanding 

 now at the outer edge into lobulate squamules; greenish-yellow; 

 apothecia of middling size, flattish ; disk tawny-yellow, the ob- 

 tuse margin soon flexuous, and crenate. Spores from fusiform 

 at length club-shaped and acicular, bilocular and irregularly 

 broken up within, often curved, ^^ mic. 



On the earth upon rocks, Colorado, Brandegee] comm. Ch. 



Jas. Sprague. With the aspect of the finer conditions of P. 



vitellinum, but clearly, though often only obscurely, stalked. I 

 also regard the remarkable development of the spores as indi- 



