. OF ARTS AND SCIENCES. 383 



FoiH* Iiiiudi'ed aud seveiity-ciglitU meeting. 



March 13, I860.— Monthly Meeting. 



The President in the chair. 



The Corresponding Secretary read letters relating to the 

 exchanges of the Academy. He also presented from the 

 author the following paper, viz. : — 



Observations on North American and some other Lichenes. By 

 Edward Tuckerman, A. M. 



Leptogidm dacttlinum, Tuckerm. in litt. : tliallo subeffuso imbri- 

 cato tenui fragili fusco-viridi, lobis minusculis adscendentibus rotundatis 

 crenato-incisis margine dactylino-dentatis ; apotheciis (mediocribus) vix 

 elevatis planis rufo-fuscis margine integerrimo albido demum disparente. 

 Spora3 ellipsoideaj diam. duplo longiores. (^yl- Syn. Lich. p. 123.) 

 "Rocks, Vermont, 3Ir. Frost. Nearest to small states of L. tre?neIloides, 

 rom wbicli it appears to be quite distinct. 



Parhelia chlorochroa, Tuckerm. in litt. : thallo substellato- 

 multifido decumbente coriaceo la3vi nudo flavo-virescente (stramineo) 

 laciniis discretis laxe intricatis repetito-dichotomis marginibus recurvis 

 (conniventibus) subtus fuscis (nigrescentibus) fibrillis nigris subpanno- 



sis ; apotheciis P. congruens, Herb. Floerk., non Ach. (Kamt- 



schatka, Titesius in herb. Floerk.) On the earth, in sterile spots, on 

 the Upper Missouri, near Fort Clark, and near Cannon-ball River, Dr. 

 F. V. Hayden. On sand, Inscription Rock (U. S. Pacif. R. R. Sur- 

 vey), Dr. Bigelow, Herb. Torr. At the Black "Water of the Platte, 

 and the head of the Platte, Rocky Mountains, Dr. H. Fngehnann. 

 Near to P. conspersa, of which it might be taken for a state, differenced 

 by its peculiar habitat ; but unmistakably related also to P. Oamtscha- 

 dalis, Ach., which was founded on a specimen from Tilesius. Floerke 

 appears to have been acquainted with the collections of the latter (as 

 see Eschw. Bras. p. 202), but referred his specimen of the present 

 Lichen to another species. The P. congruens, Ach. Lichenogr. p. 491, 

 was founded on a specimen collected by Swartz, which the latter says 

 (Lich. Amer. p. 5) inhabits trees in North America, and particularly 

 New England. (" Licolit arbores Americte borealis. In Nova Anglia 

 observata." Sw. 1. c.) "Whatever this species may prove to be, — and 

 it is now quite unknown to Lichenists, — it is enough to say that the 



