y about
1 mm. in height and 1-5 mm. in length, but the size is variable. The
color appears to depend upon the thickening of the membrane; when it is
thin and pellucid, the color is white or cinereous from the inner layer
of lime and the contained spores; with a more thickened membrane, the
color becomes ochraceous or brownish. _Physarum bivalve_ Pers. _Physarum
sinuosum_ of Rostafinski's monograph.

II. CIENKOWSKIA, Rost. Plasmodiocarp terete, elongated, flexuous,
creeping, and reticulate, irregularly dehiscent; the wall a more or less
thickened membrane, externally naked, with the granules of lime on the
inner surface. Capillitium of slender tubules, combined into an
irregular network, attached on all sides to the wall of the sporangium,
and bearing everywhere short pointed or uncinate free branchlets; the
lime in thin transverse plates and irregular nodules. Spores globose,
violaceous.

The peculiar characteristic of this genus is the short free hooked and
pointed branchlets of the capillitium.

1. CIENKOWSKIA RETICULATA, A. & S. Plasmodiocarp more or less elongated,
curved and flexuous, simple or branched, sometimes confluent and
reticulate, breaking away first along the upper surface, leaving an
irregular margin. The wall a firm yellow membrane, with thinner hyaline
areas and with thicker yellow-brown or red-brown spots; the outer
surface without any lime, smooth, and shining; the inner surface with a
dense layer of yellow granules raised at intervals into transverse
ridges, these are connected with broad thin flat plates of lime which
traverse the capillitium, forming imperfect septa to the sporangium.
Capillitium consisting of slender yellow tubules, forming a network of
irregular meshes, with slight expansions at the angles and bearing along
the sides short pointed or uncinate free branchlets; the tubules
containing a few scattered yellow nodules of lime various in size and
shape. Spores globose, very minutely warted, violaceous, 8-10 mic. in
diameter.

Growing on old wood, bark, leaves, etc. Plasmodiocarp in veins .3-.5 mm.
in thickness, sometimes forming a net-work a centimeter or more in
extent. This curious Myxomyces seems very rare in America. I have met
with it but once. The specimen in the herbarium of Schweinitz, marked
_Physarum reticulatum_, is not this species, though it answers well
enough to the original description.

III. LEOCARPUS, Link. Sporangia subglobose or obovoid, stipitate or
sess