described.
1893. _Physarum auriscalpium_ Cke., Macbr., _Bull. Lab. N. H. Iowa_,
No. 2, p. 155, in part.
1894. _Physarum virescens_ var. _nitens_ List., _Mycetozoa_, p. 59,
in part.
1899. _Physarum virescens_ var. _nitens_ List., Macbr., _N. A. S._,
p. 34, in part.
1899. _Leocarpus fulvus_ Macbr., _N. A. S._, p. 82.
1911. _Physarum fulvum_ Lister, _Mycet., 2nd ed._, p. 60.
1911. _Physarum virescens, nitens_ List., _Mycet., 2nd ed._, p. 84,
in part.

Sporangia gregarious, scattered, ovoid or globose, pale yellowish or
fulvous, opening irregularly above, stipitate; the peridium double, the
outer layer more or less calcareous, the inner delicate, almost
indistinguishable, persistent below as a shallow cup; the stipe long,
weak, striate, fulvous or yellow; hypothallus distinct, venulose, or
more or less continuous; capillitium pallid or white, dense, with here
and there below large continuous yellow calcareous nodules; columella
none; spore-mass black; spores by transmitted light, dark brown, rough,
13-15 mu. Varies to forms with single (inner) peridium and simple
physaroid capillitium. _Vid._ descriptions cited for _P. auriscalpium_,
_P. nitens_, etc.

This interesting form is from our western mountains, and suggests at
first a diderma; but the capillitium is entirely unlike that of a
diderma in color and structure, and plainly belongs here. Plasmodium
yellow, on fallen leaves and twigs. Our material is from Prof. Bethel,
Denver; and Lake Tahoe, Nevada; later from Dr. Weir, Montana. No doubt
common at high altitudes near the snow-line in mountainous regions,
probably around the world.

As indicated above, this was originally entered as of the genus
_Leocarpus_; the taxonomic history of the form may interest readers who
note with surprise the presentation in synonymy here developed.

About thirty-five or forty years ago Dr. Harkness of California sent to
Mr. Ellis of New Jersey a slime-mould which the sender referred to
_Diderma albescens_ Phillips, (_Grev._ V., p. 114, 1877). Ellis sent a
small bit to the Iowa herbarium without other comment, save that he
thought it a physarum. Sometime later Mr. Ellis received from Father
Langlois, a correspondent in Louisiana, specimens he esteemed the same
thing. He expressed the opinion that if this were what Phillips had
found in California, it should perhaps be called a physarum. The
Louisiana material by his courtesy ca