924 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
of the substratum; apothecia minute, 0.15 to 0.4 mm. in diameter, immersed and 
circular or more or less irregular in form, 1 to 3 in each areole, the disk black, flat, 
and somewhat depressed, the thalloid exciple entire; hypothecium pale; hymenium 
pale beneath and dark brown above: paraphyses simple or rarely branched, com- 
monly somewhat enlarged and brownish toward the apex; asci clavate; spores oblong- 
ellipsoid, 9 to 15 ” long and 5 to 8 » wide, often somewhat constricted at the septum, 
Collected at Battle Lake. On granite. 
A North American lichen, not known elsewhere. 
PHYSCIA Ach. Lich. Suec. 3, 170, 255. 1798. 
The thallus is usually foliose, but a few species rise to the fruticose condition, 
while at least one is possibly nearer the crustose type. In the foliose species the 
thallus shows the upper and lower cortices well developed, though in a number of 
species there is a pseudocortex of entangled hyphe instead of a cellular one; and in 
these species this pseudocortex is usually much better developed on the upper side. 
In our fruticose Physcia ciliaris the pseudocortex is scarcely developed on more than 
one side. On the whole the cortex is better developed on the upper side, and in a 
given species one may find a well-developed cellular structure above and a tendency 
toward the pseudocortical condition below, Again, species showing the pseudo- 
cortex above may scarcely show any cortex whatever below. The algal and medul- 
lary layers occupy the usual positions for dorsiventral thalli, and the radial tendency 
is not evident even in our fruticose species. Rhizoids and cilia are common struc- 
tures in the genus. Spermagones are conspicuous on many of the thalli. The algal 
symbiont is Cystococcus, 
The apothecia are sessile or subpedicellate on thes upper surface of the thallus; 
the thalloid margin is entire, crenate, or variously irregular; the disk is usually 
brown when not pruinose, and more or less concave; the hypothecium is commonly 
pale or pale yellowish or brownish; the hymenium is pale, yellowish, or brownish; 
the paraphyses are simple or branched toward the apex, and the apex is most com- 
monly enlarged and brownish; the spores are brown and 2-celled in all of ours, 
The genus seems to be closely related to Rinodina, which also has the brown 2-celled 
spores. As a whole the thalli are quite different in the two genera, but the gap is 
easily bridged by such forms as Physcia adglutinata and Rinodina sophodes. 
Fifteen distinct forms have been noted in the State, and some of them need further 
study, for though common and conspicuous, neither our Physcias nor those of North 
America generally are well understood. 
Physcias occur on trees, rocks, old wood, over mosses, and rarely on the earth, 
Type species Physcia fastigiata (Pers.) Ach. op. cit. 175, 255. 
But this is Ramatina calicaris (1..) Fr. Thus Physcia takes precedence over Rama- 
lina, being the earliername. But the final status of both hames must wait upon the 
typification of all lichen genera. @ 
KEY TO THE SPECIES. 
Section I. Cortical layer composed of entangled hyphx, 
Thallus fruticose, ascending or pendent............._. 
Thallus foliose. 
Thallus sea-green, adnate with ascending margin; white 
below. 
Margin powdery-sorediate; exciple subentire or crenu- 
late... 1. 2. speciosa, 
Margin rarely sorediate; exciple crenate ot crenate- 
foliate..... 2.0.22... 2. 2. hypoleuca. 
...-..... 38. P. ciliaris. 
