( 248 ) 
though he separates, but by no firmer character than the many-jointed 
sterigmas, the truly foliaceous, and a part of the squamulose Endocarpa 
(Endocarpon, Ny1.) refers all the rest to his Verrucaria. Habit however, 
the aggregate expression of the idea embodied in an organism, lends value 
to differences which might not otherwise attract special attention; and 
may enable us to reach constructions at least less complex than either of 
those cited. As here taken the genus before us is equivalent to the 
Acharian conception of the group, as finally reformed by Fries; and to 
Endocarpon and Dermatocarpon of Anzi. 
Starting, like Pannaria, with truly foliaceous lichens, so well marked 
indeed as to be better comparable with Umbilicaria, Endocarpon runs 
as readily as the former into squamulose conditions. £. Jfowlinsii, in its 
best forms perhaps the finest of Endocarpa, is scarcely more diverse from 
the humblest of the squamulose species, than Pannaria molybd@a and 
P. plumbea from P. tryptophylla and P. nigra. In both genera modifi- 
cations of the spore-structure lend now apparent weight to the differences 
resulting from the deterioration of the thallus; while yet in neither are 
these changes in the internal configuration of the spore confined to the 
lowest forms, but occur also in species referable fairly to the foliaceous 
type. Endocarpon pusillum, Hedw., is, on the one hand, far from unlike 
in most respects, externally, to £. (Dermatocarpon) arboreum, while, on 
the other, it is scarcely distinguishable from a lichen (End. Garoraglii 
(Mont.) Scher.) so similar often to the crustaceous Staurothele umbrina, 
that the latter might even be taken, says Nylander (Pyrenoc. p. 20) for a 
saxicoline state of the same species. ! 
In one respect the parallel with Pannaria, so far at least as present 
knowledge extends, is less close. Thesterigmas of the genus just named 
are assumed to be always jointed. This is indeed the case also in the 
higher forms of Endocarpon, and the character holds good of such 
diminished ones as £. hepaticum and E. compactium (Mass.) Nyl.; but in 
E. cinereum, E. monstrosum, Mass., and E. pusillum, we have (Nyl. 1. ¢.) 
simple sterigmas. The distinction in question, as presented in other 
groups of Lichens, is yet clearly of but subordinate value; and no good 
reason appears for laying greater stress upon it in the family before us. 
Even as here understood, Exdocarpon is a small group, but twenty- 
four species referable to it, not a few of them more or less doubtful, being 
reckoned by Nylander (Pyrenoc.) and the number having been but little 
increased since. The group is northern and austral; but extends to the 
mountains of tropical regions. Of the conspicuously foliaceous species 
1 Compare Dr. Th. Fries’s apposite remarks on his E. pulvinatum,—‘ Lichen 
maximopere insignis, melius evolutus quam Dermat. rufescens et Endoc. pusillum, 
Hedw. (Dermat. Schereri, Koerb.) sed habitu, colore, apotheciis magis cum Stig- 
matommate, Koerb. congruens ; est enim omnino ut St. clopimum thallo foliaceo, 
pulvinato-imbricato preditum.’ (Lich. Arct. p. 257). 
