Lichenes collected on the Missouri and its tributaries, by J.V. Hayden, M.D. To which are added a few others from the same region. By Edward Tuckerman, A.M. 1859 T896 pm Fam. I. Colleacei, Nyl. Leptogium saturninum (Dicks.) Nyl. Syn.p.127. Collema, Ach. Tuckerm. Synops. fertile; Lich. N.E.p.92. Rocky Mountains, Herb. Hook. Beside this there possibly more than one are probably several species, occurring with Lecidea decipiens, on the earth, at Deer Creek, North Platte; and doubtless elsewhere in similar habitats; but the fragments before me are all infertile, and otherwise too imperfect for determination Fam. II. Lichenacei, Nyl. Cladonia pyxidata (L.) Fr. Lichenogr.p.216. Black Hills of The Upper Missouri, Dr. Hayden. The horizontal thallus of another species, perhaps C. Mitruia, Tuck., occurs from the same region. (1858) Pilophorus acicularis (Ach.) Th. Fr. Comm. Stereoc.p.41. Stereocaulon (Pilophoron) acic- ulare, Tuckerm. Synops.p.47. Pilophoron, Tuck. Suppl. in Amer. Journ. Sci. 1858, p.426. On stones and dead trees. Rocky Mountains, Herb. Hook. Dead twigs. Usnea barbata (L.) Fr. Lichenogr.p.18. a.campestris, Schær. Nebraska, Dr. Hayd- en; and in the Black Hills, The same. Small, fruticulose, infert- ile states, from smooth becoming rough, and sometime foveolate (v.hirta, auct.)