hion at the top, displaying sometimes the thin membranous inner wall
but at length fissured and gaping as in the more usual phase figured by
authors, where the plasmodiocarp is simply compressed but not
extravagantly thin. Both types occur in the western mountains, forms
with and without calcium, fissured by wider or narrower cleft, _from the
same plasmodium_; forms bilabiate and forms opening at first to display
an inner peridium; forms globose with narrow base, but apex cleft, and
forms ellipsoidal, yet compressed, opening like the gaping of some
tiniest bivalve; did not Persoon say _P. bivalve_! all are bivalvular at
the last! Nay; but what are these? Here are some of the shorter forms
become suddenly obovate, and are actually mounted on _stipes_! Surely
variation in the same plasmodium can no farther go![22]

Not rare. Colorado to the Pacific Coast. Evidently a western-American
variation of Bulliard's European type. The latter occurs abundantly in
Iowa on the shores of Lake Okoboji; otherwise not common.

6. PHYSARUM BOGORIENSE _Racib._

1898. _Physarum bogoriense_ Raciborski, Hedw., XXXVII., p. 52.

Sporangia sessile, elongate, creeping but not reticulate, semicircular
in transverse section, sometimes globose or depressed globose; peridium
double, the outer thick coriaceous, yellow or brown, dehiscing
stellately into persistent more or less triangular reflected lobes,
remote from the thin, colorless inner wall; columella none; capillitium
feebly developed, the nodes white, large, isodiametric; spores bright
violet, smooth, 7-8 mu.

This species is not uncommon in the mountains of Colorado where it has
been taken at various stations by Bethel. It is reported from
Pennsylvania and South Carolina. Raciborski describes it from Java.

In habit it is very much like some forms of _P. sinuosum_ but differs in
the depressed, rather than compressed sporangia, and in the brown color
of the outer peridium.

7. PHYSARUM ALPINUM _G. List._

1910. _Physarum alpinum_ G. Lister, _Jour. Bot._, XLVII, p. 73.

Sporangia globose and sessile or plasmodiocarpous, dull yellow, smooth
or scaly; peridium double, the outer wall densely calcareous, separating
irregularly from the membranous inner wall; capillitium densely
calcareous, the nodes large, more or less branched, yellow; spores
purple brown, closely and minutely warted, 9-14 mu.

This species is based by its author upon a gathering made in California
by Dr. Hark