nules, over which
are scattered irregular white scales of lime. Capillitium of tubules
forming a loose net-work, with wide expansions at the angles; the
nodules of lime numerous, white, very large, with pointed angles and
lobes, by confluence often branched and reticulate, and occasionally
forming a pseudo-columella in the center of the sporangium. Spores
globose, minutely warted, dark violaceous, 10-13 mic. in diameter.

Growing on old wood, leaves, etc. The sporangia .4-.6 mm. in diameter,
more or less irregular. The great abundance of lime in the capillitium
and the large distinctly warted spores distinguish this species.
_Physarum cinereum_ of Persoon's Synopsis, _Didymium cinereum_ of Fries'
_Systema_. The only American specimens I have of this species are from
Iowa (_McBride_) and from Nebraska (_Webber_).

25. PHYSARUM VIRESCENS Ditm. Sporangia large, subglobose, irregular and
unequal, sessile, gregarious, sometimes crowded, but not often
confluent; the wall a thin membrane, violaceous, or in places yellowish,
with a dense layer of yellow or greenish-yellow scales and granules of
lime. Capillitium a loose net-work of tubules, with wide expansions at
the angles; the nodules of lime large, numerous, yellow or
greenish-yellow, more or less elongated, lobed, and branched. Spores
globose or somewhat irregular, very minutely warted, violaceous, 9-11
mic. in diameter.

Growing on old leaves, mosses, etc. Sporangia .5-.8 mm. in diameter,
occasionally by confluence more elongated. Though found in all parts of
the country, the species seems rare. This is not the _Physarum
virescens_ described by Rostafinski.

26. PHYSARUM RUBIGINOSUM, Fr. Sporangia subglobose, sessile, gregarious;
the wall a thin hyaline membrane, thickly covered with large irregular
scales of lime, orange to red or dark red in color, breaking up
irregularly. Capillitium of hyaline tubules, forming a loose irregular
net-work, more or less expanded at the angles; the nodules of lime
large, angular, and irregular, sometimes confluent, orange to dark red
in color. Spores globose, very minutely warted, dark violaceous, 9-11
mic. in diameter.

Growing on old wood, leaves, mosses, etc. Sporangia .6-.8 mm. in
diameter. _Physarum fulvum_ Fries S. M., III, p. 143. A rare species. It
should not be confounded with _Physarum lateritium_.

27. PHYSARUM SERPULA Morgan, _n. nom._ Plasmodiocarp roundish or oblong
to much elongated, bent, annular and flexuous, somet