148 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
from some uncertainty in any limitations that may be set to families in these closely 
related lichens, and Schneider includes the last. family, the present one, and the next 
two all in the Pannariaceae. 
Except for the Omphalarias, the lichens of the last three families have shown no 
differentiation into algal and medullary layers, and we prefer to exclude from the 
present family Ephebe with its rudimentary thallus. Likewise it seems at least 
conducive to clearness to separate the three genera of the present family from the 
much larger and more plainly foliose, lobed, and otherwise different thalli of the 
members of the next two families, 
The algal symbiont is always a blue-green alga, most commonly Polycoccus. The 
thallus is small, but foliose or foliose-squamulose, and upper and lower cortices are 
always present. The apothecia are immersed or superficial. The spores vary from 
simple and minute in the first genus to 4-celled in some of the species admitted to 
the last genus. Thus as regards spore characters, the present family is hardly so 
high as the Collemaceae, but the spores of lichens are in all probability often de- 
generate, and greater spore degeneration may be expected frequently in forms 
otherwise higher. 
ENDOCARPISCUM Nyl. Flora 47: 487. 1864. 
The thallus is plainly foliose and usually not so closely attached to the substratum 
as that of Heppia. Indeed, the whole external appearance of the thallus is quite 
like that of Dermatocarpon, and one would very naturally pass over either of our 
species as members of that genus; for the fact of the apothecia being commonly 
immersed points toward Dermatocarpon quite as much as does the general appear- 
ance. There is a good cortex on both sides, but the development is on the whole 
better on the lower side. The medullary layer is commonly well developed, though 
scarcely so in one of the species here admitted to the genus. The algal layer is also 
well represented, the alge extending well upward into the upper cellular area and 
obscuring the cellular structure. The algal cells are blue-green, but scarcely more than 
half as large as those of Heppia, with which genus the present one is frequently placed. 
The apothecia are commonly sunken into the thallus and usually indicated by an 
ostiole, though they may even become superficial and disk-like and have a thalloid 
exciple. The spores are simple, hyaline, minute, and numerous in the asci. 
The superficial resemblance of the present genus to Dermatocarpon has already 
been noted, and the species are sometimes included in that genus. However, the 
propriety of including in a single genus forms having very different algal sym- 
bionts is uncertain. On the other hand, there seems to be a somewhat close resem- 
blance between Endocarpiscum and Heppia, though as regards the algal symbiont 
the relation is rather with Sticta or Pannaria, 
Two species have been noted for the State, the second of which we place in the 
present genus because of spore resemblance and apparent similarity of algal sym- 
bionts. Also as to thallus-structure this species is quite as much at home here as in 
the genus Heppia. On rocks or earth. 
Type species Endocarpiscum guepinii (M oug.) Nyl. loe. cit. 
KEY TO THE SPECIES. 
On rocks, thallus of moderate size and thickness. .............. lL. EH. guepinii. 
On earth, thallus smaller and thinner......................... 2. EB. polysporum. 
1. Endocarpiscum guepinii (Del.) Nyl. Flora 47: 487, 1864. 
Endocar pon guepinti Del.; DC. Bot. Gal. ed. 2. 21594. 1830. 
Thallus foliose, thickened, commonly raised from the substratum toward the mar- 
gins; ours rather thicker than foreign specimens at hand and not showing the sore- 
diate border common in other material; greenish or brownish olive, flat or in ours 
more commonly variously irregular above, below smooth or wrinkled and usually 
