7.5-9 mu.

This delicate and elegant little species appears to be not uncommon, but
is probably generally passed over as an _Arcyria_, which it
superficially resembles. When newly formed, the sporangia have a
peculiar rosy or flesh-colored metallic tint, which is all their own.
Within a short time this color passes, and most of the material comes
from the field brownish or ochraceous in color. Typical sporangia are
spherical on distinct short stipes; when crowded, the shape is of course
less definite. The capillitium never expands as in _Arcyria_, but,
exposed by the vanishing upper wall, remains a spherical mass resting
upon the shallow cup-like base of the peridium.

This species has been in the United States generally distributed as _L.
incarnatus_ (Alb. & Schw.) Schroet. A careful study of all descriptions
of European forms and comparison of many specimens leads us to believe
that we have here to do with a type presenting constant peculiarities.
We have in America nothing to correspond with the figures of Schweinitz,
Berkeley, or Lister. In the American gatherings the sporangia are
uniformly regular, globose, very generally short-stipitate, more or less
closely gregarious, never superimposed, or heaped as shown in Berkeley's
figure, for instance, _Ann. and Mag. Nat. Hist._, IV., xvii., Pl. ix.,
Fig. 2. The plasmodium of our species is white; as it approaches
maturity a rosy metallic tinge supervenes, quickly changing to dull
yellow or alutaceous. The graphic description given by Fries of
_Perichaena incarnata_, _Syst. Myc._, III., p. 193, presents scarcely a
character attributable to the form before us. _L. congesta_ Berk. & Br.,
evidently the form figured and described by Lister, _Mycetozoa_, p. 194,
Pl. lxx., B., resembles our species in color and capillitium, but is
entirely different in habit.

Not uncommon. Maine, Iowa, Missouri, Nebraska.

=2. Arcyria= (_Hill_) _Pers._

1751. _Arcyria_ Sir John Hill, _Gen. Nat. Hist._, II., p. 47.
1801. _Arcyria_ Pers., _Syn. Fung._, p. 182.

Sporangia ovoid or cylindric or even globose, stipitate; the peridium
thin, evanescent to near the base, the lower part persisting as a
calyculus; the stipe variable, packed with free cell-like vesicles,
resembling spores, but larger; capillitium attached below, to the
interior of the stipe or to the calyculus, in form an elastic network,
the tubules adorned with warts, spinules, half-rings, etc., but without
spiral bands o