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U IÜ YM O S PO R IUM BETÜLINÜM.
Birch-tree Didymosporium.
C l a s s a n d O k d e i i ClïYl^TOGAMIA FUNGI, Lin n— S ax. O r d . E P IP H V TÆ ,
Link.
G EN'ERIC CHARAC TER .
Sporidia suhrotundata, didyma, conglobala, per epidermidem etnorliiam erumpen-
tiam.— Strmna spurium.— F r i e s .
Sporidia somewhat roundish, didymous, forming a mass, bursting through
the dead epidermis.—Receptacle spurious.
S P E C IF IC C HARAC T ER .
D id y m o s p o r iu m betulinum; sporidiis ovalibus, suhæqualiter \-seplaiis, atris,
in cumulum subconicum erumpentibus ; stromate depresso-conico, basi late effuso,
sulphureo.
D. sporidia oval, nearly equally uniseptate, black, bursting forth into a sub-
conical heap : the receptacle depressed-conical, spreading widely at the
base, yellowish.
D id y m o s p o r iu m elevatum, Link, Sp. PL Willd. Continuât, v. 6 . Pt. 2 .
p. 94.
Melanconium b e tu lin um , Kunze, Deidschl. Schwaem. 9- No. 208.—Moug. et
Nestl. St. Exsicc. No. 670.
S t i l b o s p o r a spcrmatodes. Link, Obs. 2. p. 30.
S t i l b o s p o r a betulinum, Pers. in lA tt.fd e Moug. el Nesller.
H ab. On the trunks and branches of dead Birch-trees (Beiula alba) ; a t all
seasons. Roslin Woods.
Plant produced beneath the epidermis of the bark, bursting through it
and becoming effused, in the form of little deep black conical masses,
1-3 lines in breadth. Spoi'idia copious, very minute, oval, didymous,
surrounding a spurious depressed-conical receptacle, widely spreading
at its base, and o f a yellowish colour; in age becoming sometimes obliterated.
The genus Didyimsporiwn, iwn for the first time represented
in a British work, was instituted by my excellent friend
Professor N e e s a b E s e n b e c k in his System der P ike und
Schwaemme. It appears to rest its character, when compared
with Melancomium, only upon the didymous sporidia. The
mm