162 LEPTOGIUM. 



only to notice the f. laciniatum, Tuckerm. in Wright Lich. Cub., 

 the narrowed and elongated, branching divisions of which ska- 

 ply follow the stems of the mosses on which the plant grows. 

 This is often a well-marked West Indian lichen ; but it has also 

 occurred in Canada, Macoun. 



I6(b). L. juniperinum, Tuckerm.; thallus smallish, micro- 

 phylline, rosulate, laciniate-lobate ; lead-coloured, and dark- 

 green; the rounded, smooth lobes ascendant, and imbricate- 

 complicate, with undulate, crenate edges; apothecia small to 

 middling-sized, zeorine, sub-sessile, flat ; the disk rufous, thinly 

 margined. Spores ovoid- ellipsoid, 4-locular becoming sub-muri- 



form, decolorate, ^J mic. Suppl. 2, I c. p. 201. L. Tremel- 



loides v. mierophyttum, Tuckerm. Gen. p. 97. 



On the earth, growing over twigs, etc., in ll cedar-brakes," 

 Texas ( Wright), Tuckerman I. c. 1859. On the earth, Alabama, 

 Peters. On rocks, Lookout Mountain, Tennessee, Ravenel. Illi- 

 nois, Herb. Willey. On rocks, Massachusetts, Tuckerman. 

 With something of the habit of growth of the European Collema 

 cheileum, and well- distinguished in this respect from all our L. 

 Tremelloides. 



16(c). L. dactylinum, Tuckerm. ; thallus microphylline, ef- 

 fuse; from lead-coloured becoming black; the originally squa- 

 maceous, ascendant, rounded lobules finally erect, with crisped, 

 entire, or crenate edges, soon fringed and beset above with 

 crowded, isidioid branchlets, and constituting at length a broken- 

 areolate, granulate crust ; apothecia small, biatorine, sub-sessile, 

 flat ; the disk red-brown ; the paler margin soon disappearing. 

 Spores ovoid-ellipsoid, from 4-locular sub-muriform, decolorate, 

 ^ mic. Obs. Lick. 1, 1. c. p. 383. Nyl. Syn. l,p. 123. 



Calciferous schist, Vermont (Frost), Tuckerman in Nyl. I. c. 

 1858. Calcareous rocks, Missouri, Hall And I cannot distin- 

 guish a rather more developed, always lead-coloured lichen 

 which much lessens the distance between L. dactylinum and L. 

 Tremelloides, and occurs on calciferous shale in New York, W. E. 

 Gerard ; on limestone at Trenton Falls, New York, Tuckerman ; 



as in New Jersey, Austin; and Illinois, Herb. Willey. In all 



these the collogonidia are however commonly solitary, or in very 

 .short chains. 



17. L. marginellum (Sw.) Mont.; thallus sub-orbicular, mid- 



