a very large, sessile
phase of _P. polycephalum_. See further under that species.

Europe, Japan, Eastern United States (?).

54. PHYSARUM POLYCEPHALUM _Schw._

PLATE VIII., Figs. 2, 2 _a_, 2 _b_.

1822. _Physarum polycephalum_ Schw., _Syn. Fung. Car._, No. 382.
1829. _Didymium polycephalum_ (Schw.) Fries, _Syst. Myc._, III.,
p. 122.
1837. _Didymium polymorphum_ Mont., _Ann. Sci. Nat._, Ser. 2, 8,
p. 361.
1837. _Didymium gyrocephalum_ Mont., _op. cit._, p. 362.
1875. _Physarum polymorphum_ (Mont.) Rost., _Mon._, p. 107.
1875. _Tilmadoche gyrocephala_ (Mont.) Rost., _Mon._, p. 131.
1899. _Tilmadoche polycephala_ (Schw.) Macbr., _N. A. S._, p. 57.
1911. _Physarum polycephalum_ Schw., List., _Mycetozoa, 2nd ed._,
p. 58.

Sporangia spherical or irregular, impressed, gyrose-confluent,
helvelloid, umbilicate below; peridium thin, ashy, covered with
evanescent yellow squamules, fragile; stipe from an expanded
membranaceous base, long-subulate, yellow; spores smooth, violet, 9-11
mu.

A most singular species and well defined is this, occurring in masses of
decaying leaves or on rotten logs. The plasmodium at first colorless; as
it emerges for fructification, white, then yellow, spreading far over
all adjacent objects, not sparing the leaves and flowers of living
plants; at evening slime, spreading, streaming, changing; by morning
fruit, a thousand stalked sporangia with their strangely convoluted
sculpture. The evening winds again bear off the sooty spores, and naught
remains but twisted yellow stems crowned with a pencil of tufted silken
hairs. August.

Although Rostafinski's description of this species is accurate and marks
exactly a _Tilmadoche_ and is very different from his description of
_Physarum polymorphum_, nevertheless it is probable that both
descriptions have reference to the same thing. All specimens on which
both species were based were American; _P. polymorphum_, North American.
But the only North American form to which reference can be made is that
by Schweinitz called _P. polycephalum_ and, fortunately, sufficiently
described. Furthermore, Rostafinski, under _T. gyrocephala_, himself
affirms the probable identity of Montagne's _Didymium gyrocephalum_ with
the Schweinitzian species, and uses Montagne's specific name
provisionally. For these reasons it seems proper to write the species as
above.

Widely distributed and common, from Maine and Canad