(34) 
guish it from Nephroma. A conclusion scarcely indeed surprising in view 
of such Sticte as S. hirsuta, Mont. ! 
The different structure of the gonidia (upon which Schwendener, l. c. 
p. 183, and passim, and De Bary, Morph. u. Phys. d. Pilze, ete., p. 257, are 
especially instructive) in the large group of species represented by 8S. 
quercizans (Stictina, Nyl.) from that in the group of which S. damecornis 
may be considered a prominent type (Sticta, Nyl.) — first indicated indeed 
in aremark of Tulasne,! but only given full expression to by Nylander 
(Flora, 1860, p. 65. Syn. 1. c.) is perhaps the most important observation 
that has been made upon Sticta since the genus was first distinguished by 
the cyphelle; and has proved an invaluable guide in the study of the 
species. But it appears none the less true that the two vast species 
named belong without doubt to one and the same natzral genus; and the 
difference relied on to distinguish them sinks in fact fairly out of sight, in 
the preponderance of affinities which unite them. Ricasolia De Not., Nyl. 
l. c., agreeing with Sticta, Nyl., in the gonimous layer, embraces the ele- 
gant group of species represented by S. amplissima and S. dissecta, 
and is distinguishable if not by habit at least by the general absence of 
cyphelle; but the latter are well-marked in S. Wrightii (Tuckerm. Suppl. 
2, 1. ¢. p. 204) which offers other points of resemblance to the wider con- 
ditions of S. damecornis; —and nothing else appears to separate it. 
It has already been suggested, and is perhaps sufficiently evident that 
Sticta occupies an extreme position in the present family, whether we 
regard its relations to the two families next immediately preceding it, or 
to the type of Peltigereine structure with which its own is most closely 
associated. And its range contrasts also with that of the Peltigerei 
proper. Sticta is mainly tropical, a large proportion of the species (as 
compare Nyl. Syn. 1, p. 333) occurring also in, or confined to austral 
regions, but scarcely a fifth known in the northern temperate ones, where 
about half the prominent forms occur only sterile. Rather more forms 
have been observed in Europe than have yet been detected here. I have 
seen no American specimens of 8. limbata, S. Dufourii, or S. herbacea; 
nor has the tropical S. damecornis found a home with us, as in the south 
of Ireland. But another species of the warmer regions of the earth (4. 
quercizans) not remote from S. sylvatica, is frequent, though infertile, in 
almost every part of the United States; and the place of S. herbacea 
may be said to be taken in all the extreme southern portion of the coun- 
try (from South Carolina to Louisiana) by the also tropical S. Rarenelit 
(T. Suppl. 2, 1. c. p. 203, and in Wright Lich. Cub. n. 66. Ricasolia. Nyl. 
Prodr. N. Gran. p. 24).!. But little else has been added to our list. 
8. fuliginosa, Ach., was found by me, on rocks, near Boston, in 1848; and 
“ Ses gonidies,” he says of Sticta sylvatica, “resemblent plus a celles des 
Peltigera qwaux gonidies du Lichen ci-dessus décrit” (S. herbacea).—Mém. sur les 
Lich. p. 21, 
