Sporangia globose, flattened or lenticular, beneath plane or concave,
variously colored, yellow, greenish yellow, rusty orange, stipitate,
nodding; the peridium splitting irregularly or reticulately; stipe
variable in length and color, through various shades of red and yellow,
subulate; capillitium strongly developed, concolorous with sporangium,
the tubes with colorless or yellow calcareous thickenings; spores
smooth, fuscous or violet-black, 8 mu.

A very handsome and rather common little species; like the preceding,
but generally greenish-yellow in color, and occasionally brilliantly
orange without a suggestion of green. Indeed, the color is so variable
that some authors have been disposed to discard the species entirely,
inasmuch as the chief specific character is color. The plasmodium is
pale yellow, in rotten logs, stumps, etc. In the paler yellow or
greenish forms the stipe is more commonly black.

This is _Physarum luteum_ (Bull.) Fries, and likewise also includes the
three varieties, _viride_, _aureum_, _coccineum_, listed by the same
author under _P. nutans_, while he at the same time remarks that they
might with equal propriety be elsewhere referred. Rostafinski considers
that all the colored forms agree in capillitium sufficiently to be
associated under one name and are in the same way unlike _T.
nutans_.[29] Rostafinski thinks to avoid confusion by suggesting a more
fitting specific name, _T. mutabilis_, but there seems no good reason
for not adopting the earliest identifiable specific appellation, which
in this case appears to be _viride_. The yellow phase is common in Iowa,
resembles in size, color, stipe, _P. galbeum_ Wingate, but is instantly
distinguishable by the capillitium. _N. A. F._, 1213.

Widely distributed specimens are before us;--from New England, New York,
Pennsylvania, Maryland, Ohio, Nebraska, Iowa, California, Oregon,
Canada, Nicaragua, Samoa, Alaska, India, etc.

=EXTRA-LIMITAL=[30]

PHYSARUM MUTABILE (_Rost._) _List._

1875. _Crateriachea mutabilis_ Rost., _Mon._, p. 125.
1892. _Crateriachea mutabilis_ Rost., Mass., _Mon._, p. 344.
1894. _Physarum cinereum_ List., _Mycetozoa_, p. 55, in part.
1895. _Physarum crateriachea_ List., _Jour. Bot._, XXXIII., p. 323.
1910. _Physarum crateriachea_ List., Petch, _Mycetozoa Ceylon_,
p. 336.
1911. _Physarum mutabile_ List., _Mycetozoa, 2nd ed._, p. 53.

Sporangia cylindrical ovoid or sub-globose white, plasmo