(56 ) 
in P. nebulosa, Nyl. Lich. Par. n. 114) throughout of rounded cells (diam. 
0,007-0,011"™™-) and collogonidia which are commonly solitary, and only 
rarely concatenate in threes and fours. Apothecia (reaching at length 
1”™- in width, but more often smaller) innate-sessile, reddish-brown, darker 
perhaps, but otherwise very similar in aspect to those of the cited German 
specimen, except that in the Illinois lichen, in which the thallus is espe- 
cially well-developed, this more evidently conditions the here almost 
lecanorine fruit. Spores in eights, ovoid-ellipsoid, muriform-plurilocular 
(long. ser. 4-6, more rarely 8; transv. ser. 2, rarely 3) pale-brownish 
while in the thekes, and now also when free, 0,0]8—0,30™™- long, and 
0,007-0,014™™- wide. Often exactly resembling, in the spores, Leptogium 
lacerum and ZL. subtile (or as in Arn. Lich. Fragm. in Flora, 1867, t. 1, 
f. 6) but our plants are easily distinguishable by the differences of the 
thallus. I can entertain no doubt (and compare also the remarks of 
Koerber, 1, c.1) that the German plant cited is a true Pannaria; and 
the Illinois lichen here above described appears properly referable to it. 
The Massachusetts specimens are inferior in the thallus but similar in 
the apothecia and the spores. Hymenial gelatine becoming intensely 
blue with iodine. 
Excluding the first section (Psoroma, Nyl.) of nine species, as reck- 
oned by Nylander, which attains to its perfection only in the austral 
regions of the earth, the great bulk of Pannaria, of something less than 
forty species, appears certainly to be northern; but this is due to the 
number of reduced forms oceurring northward; and, looked at in the 
light of its best-developed conditions, the genus is in fact largely south- 
ern, and analogous in this to Sticta. Rather less than half of the whole 
number of species has been detected in North America; and the Euro- 
pean ratio is much the same; but no doubt forms remain to be observed 
on this continent. 
Fam. 6.—COLLEMEIL. 
Thallus frondoso-foliaceus 1. dein crustaceo-diminutus, rarius fru- 
ticuloso-adscendens 1. alectoriiformis, cartilagineo-l. coriaceo-mem- 
branaceus, humidus in plerisque subgelatinosus, hypothallo fere 
semper obsoleto. Stratum gonimicum plerumque inordinatum dis- 
1 “Sie ist unter allen Collema-arten diejenige, welche am wenigsten dem Gat- 
tungstypus entspricht, da sie die fiir Collema (und verwandte Gattungen) so char- 
acteristisehe wasserhelle Pulpa mit den darin vertheilten Faserclementen durchaus 
nicht besitzt, auch die Microgonidien der Thallus etwas grésser sind, und sich 
seltencr zu den bekannten Gonidien-schniiren verbinden.” Koerb. Parerg. p. 410. 
