Sporangia irregular, often convolute,
involved 54. _P. polycephalum_

2. Sporangia simple, nutant, discoidal.

_a._ Thin-walled, grey or white. 55. _P. nutans_

_b._ Vari-colored, yellow, greenish,
orange, etc. 56. _P. viride_

1. PHYSARUM SERPULA _Morgan._

PLATE IX., Figs. 6, 6_a_, and 6_b_.

1831. _Physarum reticulatum_ Alb. & Schw., Schweinitz, _N. A. F._,
No. 2295.
1885. _Physarum gyrosum_ (Rost.) Wingate, Ellis, _N. A. F._, No. 1396.
1892. _Physarum gyrosum_ Rost., Massee, _Mon._, p. 307.
1892. _Cienkowskia reticulata_ Rost, Macbr., _Bull. Nat. Hist. Iowa_,
II., 2, p. 150.
1894. _Badhamia decipiens_ Berk., Lister, _Mycetozoa_, p. 33, in part.
1896. _Physarum serpula_ Morg., _Cin. Soc. Nat. Hist._, p. 101.
1899. _Physarum serpula_ Morg., Macbr., _N. A. S._, p. 29.
1911. _Physarum serpula_ Morg., Lister, _Mycetozoa, 2nd ed._, p. 81.

Plasmodiocarp repent, reticulate, forming anon lines, circles, dots,
etc., venulose pale yellow, ochraceous, at length whitish, the peridium
thin, membranaceous, simple, fragile, but withal persistent, below
united with a hypothallus which is more or less widely produced;
capillitium rather scant, but abundantly charged with polygonal nodules
of lime, yellow; spore-mass black; the spores, by transmitted light,
violaceous, warted, globose, 10-13 mu. Plasmodium, at maturity,
greenish-yellow.

A very distinct species not likely to be confused with anything else,
although in description, so far as concerns external characters,
suggesting _Cienkowskia reticulata_. The two forms are not at all alike
when placed side by side. For details as to the difference, see the
description of the species last mentioned.

Apparently not rare in eastern United States, Pennsylvania, Virginia,
Ohio, Iowa.

In 1805, Albertini and Schweinitz, _Conspectus Fungorum_, p. 251, t. 7,
Fig. 2, described as _Physarum reticulatum_, a European form which
became the basis of Rostafinski's genus _Cienkowskia_; see under that
genus. Later, 1829, Schweinitz discovered in America a physarum-looking
specimen which he took to be the same thing, and accordingly placed in
his herbarium under this name, and entered _N. A. F._ 2295. Rostafinski
further renamed another Schweinitzian species _Fuligo muscorum_ calling
it, _Mon._, p. 111, _Physarum gyrosum_. Wi