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characters. The evolution of the spores indicates plainly a two-fold 
nisus, observable not merely in Collema as a whole, as here taken, 
but even within the narrow limits of a single species;— C. flaccidwm 
offering, in a word, as will be seen below, unmistakable exhibitions of 
both the acicular and the muriform spore-types. Nor are the, here 
important, thalline characters always clear as yet; though we venture, 
to some extent, to rely on our interpretation of these, in bringing together 
some hitherto widely separated clusters. 
Sect. 1.— CoLLEMELLA. 
1. C. cladodes, Tuckerm.! lLime-rocks, Trenton Falls, New York. 
Analogous here to Leptogium dendriscum in the genus immediately 
following. 
Sect. 2.—LATHAGRIUM. 
2. C. myriococcum, Ach., Nyl., Arn. Growing over mosses, on lime- 
rocks, Rockland county, New York (Mr. Austin). <A similar plant occurs 
at Trenton Falls, but infertile. Spores simple, from roundish becoming 
ovoid or even ellipsoid, disposed, in a single series, in narrowed, or more 
rarely otherwise, in ventricose thekes. C. chalazanum, Ach., is kept 
separate (not without hesitation) by Nylander, and, more decidedly, by 
Arnold; but the distinction appears to be difficult. Of the two names, 
myriococcum was the first published. The fully developed thallus of this 
species looks evidently in the same direction with that of C. omphalari- 
cides, Anz. (L. Etr. n. 46) and the latter plainly corresponds, not only, as 
its author suggests, with C. aggregatum, but no less with C. pyenocarpum. 
——3. C. pycnocarpum, Nyl. Trunks, common in New England and the 
northern states. Ohio (Lesquereux). Illinois (E. Hall). South Carolina 
(Mr. Ravenel). Alabama (Mr. Peters). This lichen and the next are 
representatives here of the much less conspicuous C. conglomeratum, 
Hoffm., and recently separated C. verruculosum, Hepp, of Europe; and 
all together make one natural cluster, or species sensz latiori. C. con- 
glomeratum, and the two American members of the cluster, belong to 
Synechoblastus, as understood by those who receive that group as a genus; 
but C. verruculosum, however closely akin to the rest, and associated 
with C. conglomeratum by Arnold J. c., is none the less, and in the same 
restricted sense, a Collema. Compare the still more striking instance of 
1 Collema cladodes (sp. nova) thallo pumilo cartilagineo fruticuloso pulvinato 
atroviridi, ramis teretibus longitudinaliter tenuissime striatis fastigiato-subramosis, 
periphericis stellato-radiantibus ; apothectis minutis terminalibus lateralibusve 
depresso-globosis. Thecw conferte clavate; paraphysibus parcis irregularibus. 
——tTrenton, N.Y. Thallus not much exceeding a quarter of an inch in diameter, 
with the texture and colour of Collema; the concatenate collogonidia interspersed, 
among anastomosing filaments. Perfect apothecia scarcely seen. 
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