286 PROCEEDINGS OF THE AMERICAN ACADEMY 



longo-ellipsoitleis, (sporobl. integris,) diam. 3-5° longlores. Arthonia 

 cyrtodes^ Nyl. 1. c. On trunks in the island of Cuba, Mr. Wright 

 (Lich. Cub. n. 245). 



/3. Thallus dein cinerascens hypothallo nigro, sporis magis oblongis, 

 (sporobh nunc muriformi-divisis,) diam. 3-4° longiores. Arthonia 

 distendens, Nyl. 1. c. With the other, in the island of Cuba, Mr. 

 Wright (Lich. Cub. n. 246). 



I had referred this to Lecidea (in herb., as an aberrant type of the 

 group Heterotheciuvi), but the exciple is absolutely deficient, and the 

 lichen belongs, as determined by Dr. Nylander (to whom specimens 

 were sent, in advance of publication, and published by him), to Arthonia. 

 I am still, however, unable to discern in the specimens more than the 

 development of a single species. As respects the thallus, the apothecia, 

 and the spore-sacks, both forms entirely agree. The hypothallus be- 

 comes possibly more distinct in /3, and there conditions more or less the 

 color of the thallus, which varies at length in this form, to brownish. 

 The spores, quite similar in their younger states (varying from 2-5- 

 locular) in both forms, become a little dilated in /3, and the sporoblasts 

 (entire in a) are then here and there divided, and thus first indicate 

 the true type of the lichen : exactly as occurs in other spores of the 

 muriform sort, where the same process of differentiation (from narrower 

 and more ellipsoid forms, with entire sporoblasts, to more dilated ones, 

 with subdivided sporoblasts) is observable abundantly in the contents 

 of the same thalamium. 



Verrucaria Drummgndii, sp. nov. : thallo determinato subcarti- 

 lagineo rugoso-veiTucoso ambitu radioso-subplicato nigricanti-fusco 

 hypothallo indistincto ; apotheciis minutis verrucis thallinis immersis 

 ostiolo prominulo nigro. Sp. in thecis saccatis (1 - 2na3 ?) majusculce, 

 e cocciformi oblongte, muriformi-polyblastJB, nigro-fusca?, diam. Ig- - 

 3^° longiores. On lime-rock, near Kingston, Canada. The small, 

 rounded, thinnish, and very dark fronds are quite conspicuous on the 

 light-gray rock, and are from a quarter to half an inch in diameter. 

 Thallus warted at the centre, but passing into wrinkles towards the 

 circumference, which is more or less distinctly plaited, and radiant in 

 a manner sometimes approaching that of Lecidea (Sporostatia) Morio, 

 or, still more, some hypothalhne fringes of crustaceous rock-lichens. 

 Apothecia contained in larger, pretty regular warts, the white perithe- 

 cium finally blackening, especially above. Paraphyses scarcely ob- 

 servable, but the " liymenial gonidia " especially abundant. The 



