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XXXI.—CONOTREMA, Tuckerm. 
Tuckerm. Syn. N. Eng. p. 86. Koerb. Parerg. p.105. Th. Fr. Gen. p. 75. 
Stizenb. Beitr. 1. c. p. 158. Lecides sp., Ach. L. U. p. 671; Syn. p. 27. 
Lecidee sect., Nyl. Enum. Gén. p. 127; Add. nov. ad Lich. Eur. in Flora, 
1867, p. 329. 
Apothecia urceolata, truncato-conoidea, subinde patellato-aperta, 
excipulo proprio atro; thallino tenui, evanido. Spore cylindracee, 
pluriloculares, incolores. Spermatia haud visa. Thallus crustaceus, 
uniformis. 
C. urceolatum, originally found by Swartz, and by Muhlenberg in Penn- 
sylvania, but equally common in New England and Virginia, extending 
southward indeed (in the mountains) to South Carolina (Mr. Ravenel) 
and ascertained recently to occur also in Germany (Koerber, 1. c.) is the 
only species known to me; but Dr. Nylander describes his Lecidea homa- 
lotropa (Nyl. Add. ad Lich. Eur. 1. suprac.) as of the same type with, 
and yet specifically distinct from C. urceolatwm. The apothecia of the 
latter become finally somewhat explanate, and patelleform. Spores of 
the American lichen long-cylindraceous, 30-40-locular, and reaching the 
length of 0,160™™". Whatever the external resemblance of Conotrema to 
Gyrostomum, Fr., —and the former was closely associated with the latter 
by Acharius, and doubtfully by Fries (S. O. V.) their spores separate the 
two plants obviously and widely. 
It is only as an extreme member of the present sub-family, — itself, in 
not a few other instances, on the verge of exclusion from the tribe — that 
the type before us can be associated with Parmeliacei. There is yet a 
certain degree of resemblance in Conotrema to Urceolareine types, as 
perhaps especially to Gyalecta; and, with one important exception, the 
lichen has been placed, by the more recent writers who have considered 
it, in proximity either to Thelotrema, or to Gyalecta. It is not so easy to 
follow Nylander in making it an appendix to his Lecidea; especially as 
he does not hesitate to associate the very similarly aberrant Gyrostomum, 
Fr., with Thelotrema. But Gyrostomum looks away from the present 
family rather in the direction of certain Graphidacei; it is interesting 
therefore that the learned writer just cited has more recently suggested, 
in view of the European lichen described by him as Lecidea homalotropa, 
that this, together with Conotrema urceolatum, from which the first is 
said to differ particularly in its flat apothecia (‘precipue apothectis 
planis’) may possibly be better referable to Melaspilea, Nyl. The latter 
was indeed first published nine years after the publication of Conotrema; 
but it appears certainly difficult to detect any especially noteworthy 
resemblances between the lichens named which are not sufficiently coun- 
terbalanced by the discrepancy in their spores. 
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