750 Bcichmann . — A New Type of Spermogonium and 
found by Stahl, Sturgis, Tulasne, or others who have described either the 
carpogones or spermogonia of C. pulposum , the identification of the species 
has become a question of prime importance. It appears that what is known 
as C. pulposum , (Bernh.) Ach., varies considerably. Acharius (2) gives 
five varieties : crispum , cristatum , aphaneum , granulatum , and prasinum. 
Schaerer (29), in 1842, gives two varieties, vulgaris and prasina . Nylander 
(28) gives five : formosum , comp actum, hydrocharum , prasinum , and tenax. 
Tuckerman (34) writes of £7. pulposum , ‘ It is without doubt largely 
represented in North America, but abounds peculiarly in difficulties 
which do not appear to be as yet resolvable in Europe ; as certainly 
not here. With present knowledge, beside what may vaguely be taken 
for true C. pulposum , the group may be considered as represented with us 
by the five following, at least sub-species, the claims of which to higher rank 
are left open.’ These five are: C. tenaxum , (Tuck.), C. tenax , (Sw.) Ach., 
C. crispum , Borr., C. limosum , Ach., £7. coccophorum , Tuck., and C. p lie atile, 
Schaer. 
The form of £7. pidposum which I have studied may be described as 
follows: Thallus, when young orbicular, later becoming quite irregular, 15 
to 60 mm. long, upper surface smooth or sometimes granuloso-lobulate, 
especially about the immersed apothecia ; when wet gelatinous but quite 
firm, dark olive green above and below, or lead-coloured or yellowish green ; 
when dry brittle, much shrivelled and almost black, or, especially in case of 
yellowish green thalli, the shape and colour little changed in drying ; 
attached to the soil by numerous light to dark brown simple or branched 
rhizoids 4 to 7 microns in diameter ; marginal lobes more or less ex- 
panded, sometimes repand-crenate, sometimes imbricated, 1 to 1-5 mm. thick, 
sometimes showing a rosulate arrangement, or both marginal and central 
lobes somewhat erect ; Nostoc filaments more numerous near the surfaces ; 
apothecia developing quite close together and almost covering the central 
part of the thallus, rounded, 1-5 to 4-5 mm. in diameter ; when young im- 
mersed in slightly raised areas of the thallus, sessile, at first concave, later 
concave or convex ; disc at first pale green, later reddish-brown, margin from 
entire becoming rugose-crenate ; hypothecium almost colourless to light 
brown ; hymenium light brown above ; paraphyses brown in potassium 
iodide, septate, 1 to 3 microns wide and no to 160 microns long, simple or 
branched near the base, tips somewhat enlarged ; asci clavate, blue in potas- 
sium iodide, 18 to 25 microns wide and 95 to 140 microns long ; spores 8, 
hyaline, brown in potassium iodide, oblong-ellipsoid, muriform, 10 or 18 
celled, 17 to 30 microns long and 7 to 13-5 microns wide. 
Stahl and those who have described the spermogonia in Collema pid- 
posum may have had what Tuckerman (34) designates as the ‘ true C. pul - 
posum\ Sturgis worked with some American form. He states that his 
observations agree in all respects with those of Stahl. He gives but one 
