OF ARTS AND SCIENCES : APRIL 12,' 1864. 285 



Hong Kong specimen formerly collected by Mr. "Wright) between the 

 shorter and longer forms. The large and handsome apothecia of this last 

 condition (Lecid. proximata, Nyl.) place it at the head of our specimens, 

 as suggesting even the still more conspicuous and very distinct Lecanactis 

 Leprieurii {Lecidea, Mont. Guyan. p. 38), which, as is remai'ked by 

 Dr. Nylander (1. c), is clearly a member of the present group of species, 

 and perhaps the culmination of it. 



We have only left to notice a North American expression of the 

 type of L. premnea, diverging from the European in a direction oppo- 

 site to that which has been considered, and offering, possibly, rather 

 more evidence of distinction. Lecanactis cidoroconia, Tuckerm. herb., is 

 a rather rare New England lichen, found by me in the White Moun- 

 tains, growing on rock-maple, and in Hampshire, Massachusetts, on 

 chestnut, and sent to me by my friend Mr. Russell (with dissections 

 indicating its relations to Lecanactis), from Vermont {Mr. Frost), which, 

 with a very thin, glaucous-cinerascent, or often almost obsolete thallus, 

 not at all unlike that of conditions of L. premtiea, and similar but 

 thinner-margined apothecia, combines small, more often exactly dacty- 

 loid, quadrilocular spores, not exceeding one third of the size of those 

 of the form proximata. As compared with the last, this may well be 

 taken for distinct, but the range of its variations is as yet, perhaps, too 

 imperfectly known. 



Opegrapha microctclia. 0. myriocarpa, Tuckerm. Suppl. I. 

 (Amer. Journ. Sci. 25) p. 429, non Mont. The name originally given 

 to this lichen, occurring in several parts of New England, had been 

 previously applied to a South American species by Montagne. The 

 present has also the advantage of indicating the curious peculiarity of 

 the plant, which is its minute, rounded apothecia. 



Arthonia (Arthothelium) cyrtodes, sp. nov. : thallo tenui subcar- 

 tilagineo contiguo inaiquabUi rimuloso glauco-cinerascente hypothallo 

 nigro sublimitato ; apotheciis submediocribus adnatis rotundatis con- 

 vexis fusco-nigricantibus intus concoloribus. Sp. Snte in thecis ventri- 

 cosis, majuscul*, incolores (I'arius dein fuscidulte) oblongo-ellipsoideas, 

 10-12-blastae (sporobl. nunc hie illic muriformi-divisis), S£epe curvulse, 

 diam. 3-5° longiores. Paraphyses obsoletge. Lecidea cyrtodes, Tuck- 

 erm. in litt. Arthonia cyrtodes & A. distendens, Nyl. in Prodi-. Fl. 

 N. Gran. 1. c. 



a. Thallus viridi-glaucescens hypothallo minus distincto, sporis ob- 



VOL. VI. 29 



