( 94) 
matis spp., Hoffm. D. Fl. 2, p. 98. Ach. L. U.; Syn. p. 308. Eschw. 
Syst.; et in FL Bras. p. 231. Fée Essai et Suppl. Scher. Enum. 
Parmelie spp., Ach. Meth. Mey. Entwick. Scher. Spicil, p. 511. 
Parmeliz spp., et Patellarie spp., Wallr. Fl. Crypt. Germ. Lepto- 
gium, et Collematis sp., Fr. Fl. Scan. p. 293; Summ. Veg. Scand. p. 
122. Tuck. Syn. N. Eng. Leptogium, Mallotium, et Stephanophorus, 
Flot. Mont. Apere. Morph. Collematis spp., Leptogium, Polyscuid- 
ium, et Mallotium, Mass. Mem. pp. 83-5, 86. Mallotium, Leptogium, 
et Polyschidium, Koerb. Syst. p. 417. Mudd. Man. Brit. Lich. p. 44. 
Krempelh. Lich. Bay. p.97. Mull. Principes de Classif. p. 82. Lep- 
togium et Polyschidium, Anz. Catal. Sondr. p. 5. Th. Fr. Lich. Arct. 
p. 282. Stizenb. Beitr. 1. c. p. 144. 
Structuram descripserunt Tulasne, Mém. pp. 30, 46, 178, t. 6, f. 
10-12; Schwendener, Untersuch. 1. c. 3, p. 153, 4, p. 183, t. 23, f. 1, 2. 
Apothecia subscutelleformia, lecanorina 1. pseudo-biatorina. 
Spore ovoideo-ellipsoidee, 1. simplices, 1. dein fusiformi-elongate 
bi-pluriloculares, 1. sepissime muriformi-pluriloculares, subincolores. 
Spermatia oblonga; sterigmatibus articulatis. Thallus foliaceus aut 
rarius fruticulosus; strato corticali distincto; collogonidiis seepissime 
moniliformi-concatenatis ; filamentis medullaribus conspicuis laxis. 
Medulla nune parenchymatica. 
If the Lucollemei may be considered as ascending from certain crusta- 
ceous types, in themselves not always distinguishable without difficulty 
from others which descend from Pannaria, it is scarcely less clear that 
the extreme of development of Collemeine vegetation now before us 
reverts also to the same higher group; and displays thus the same affin- 
ity which was recognizable in its beginnings. The approaches are indeed 
mutual; nor does it appear to be necessary, at this place, to more than 
refer again to the significant examples already elsewhere cited. Panna- 
ria lurida, outcome only of a series of structural modifications all looking 
the same way, may be said, in short, to exhibit a satisfactory transition 
to Collemeine structure in a plant still inseparable from Parmeliacei ; 
and Collema byrseum, whether we take it for an imperfect Leptogium, or 
rather, with Massalongo, for a sufficiently characterized intermediate 
type (Physma, Mass.) approaches Pannaria similarly from the other 
direction. 
The whole probable number of species of Leptogium known, is less 
than that of Collema, and will not perhaps, if we leave out of account 
several little known, inferior types, looking towards the next preceding 
family, much exceed thirty. Although the larger part of what has been 
described belongs to the colder regions of the earth, almost all the finest 
examples of the genus are intertropical. We possess, here, as yet about 
one half of the whole, and the number will not improbably be increased, 
