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differentiation find interesting examples (contrasting curiously in other 
respects with Lempholemma, Koerb., as with Collema pycnocarpum, 
Nyl.) in L. dendriscum, Nyl., and L. muscicola. The group reaches its 
highest development in the large cluster of species of which Z. Tremel- 
loides is the most widely diffused type. But Mallotium, Flot., however 
now contrasting in habit, and always in the tomentose nap of its under 
side, is, on the whole, ill enough removable from the nearest neighbour- 
hood to the cluster just named. And almost the same may be said of 
Hydrothyria, Russ.; which, if Mallotium be the Sticta, may be called the 
Peltigera of the Eucollemei. 
Norte. — The structure of the plants before us has been illustrated by Schwen- 
dener in the last part of his Researches ( Untersuch. 1. c. 4 (1868) p. 174). Accord- 
ing to him, Pannariacee (from which he finally distinguishes Lecothecium, Ptery- 
gium, Lichina, &c., to constitute his Raccoblennaceew) Ephebacee, Collemacee, and 
Omphalariacew are groups of equal rank, and naturally associable in this order; 
but only the last two are entitled to be especially distinguished as Jelly-lichens. 
The peculiarities of the Jelly-lichens may be reduced essentially to 1, the dissolu- 
tion of the thickened, gelatinous membranes (principally of the gonidia, but in 
part also of the medullary filaments) into a structureless pulp, and 2, the modes of 
division, and hence of the grouping of the gonidia. Other features, as, for instance, 
the equal distribution of the gonidia throughout the tissue of the thallus, (thallus 
homeomericus) are not properly characteristical, since they are not unknown else- 
where, and in families remote, systematically, from the present. Save in the two 
points just noted, Leptogium, in its highest expressions (Jfallotium, Flot.) must 
therefore (the inference is fully justified by our author’s remarks) be generally com- 
parable with Sticta and Nephroma; and there is no doubt of the strict anatomi- 
cal resemblance of all these types, as respects as well the constitution and habit 
of the cortical layer, and of the fibrillose nap of the under side, as even the on the 
whole predominant, symmetrically divergent (or orthogonal-trajectory) disposition 
of the medullary filaments. Schwend. 1. c. passim. The observations of the 
same author on the gelatinous thickening of the membranes of the gonidia in cer- 
tain Pannarie has been cited elsewhere; but this change in the constitution of 
the cells in question is not confined to Collemei, andits next of kin, Pannariei, but 
characterizes, more or less, the blue-green gonidia' (Schwend. 1. c. 3, p. 133. Dé 
Bary Morph. u. Phys. d. Pilze, &¢c., p. 259) wherever these occur; or, at least, to 
copy Schwendener’s instructive list, at the place last cited, of the genera which 
are structurally thus associable, in “ Sticta (pr. p.) Nephroma, Peltigera, Solorina, 
Pannaria, Micarea, Lecothecium, Raceoblenna, Pterygium, and Lichina.” Is it 
questionable, then, from the purely anatomical point of view, that the Collemei 
are the outcome of modifications of Parmeliaceous structure ? 
XXIIL—SYNALISSA, Fr., Nyl., emend. 
Fr. 8. 0. V. p. 297. Collematis sp., et Pyrenule sp., Ach. Syn. p. 121, 
1 Granula gonima, Nyl., for which, as it is not questioned that these are really 
gonidial cells, the perhaps better-descriptive term, collogonidia, has been preferred 
in these pages. 
