F._, No. 2301 (?).
1869. _Diderma citrinum_ Peck, _Rep. N. Y. Mus._, XXII., p. 89.
1870. _Physarum citrinellum_ Peck, _Rep. N. Y. Mus._, XXXI., p. 55.
1894. _Craterium citrinellum_ List., _Mycetozoa_, p. 74.
1899. _Physarum caespitosum_ Schw., Macbr., _N. A. S._, p. 37.
1911. _Physarum citrinellum_ Peck, List., _Mycetozoa, 2nd ed._, p. 62.

Sporangia gregarious, or scattered globose, short-stipitate, pale yellow
or ochraceous, smooth or slightly roughened by the presence of minute
lime-particles; peridium more or less distinctly double, the outer
calcareous, fragile, the inner very delicate, with here and there a
calcareous thickening, ruptured irregularly; stipe very short, half the
sporangium, fuliginous, furrowed, expanded below into an imperfectly
defined hypothallus; capillitium abundant, the nodes stellate-angular,
large, the internodes delicate, short; spore-mass black, spores
violaceous-brown by transmitted light, strongly spinulose, 10-12.5 mu.

A very distinct and handsome species. Easily recognizable at sight by
its large, globose, almost sessile and yet distinctly stalked sporangia.
The color to the naked eye is pale ochraceous or buff. Only under a
moderate magnification do the citrine tints come out.

In the _Twenty-second N. Y. Report_, Dr. Peck incorrectly referred this
species to _Physarum citrinum_ Schum. On the appearance of Rostafinski's
_Monograph_, Dr. Peck in his revised list, _l. c._, writes _P.
citrinellum_ Peck, with description on p. 57, following. Under the last
name the species has been generally recognized in the United States and
distributed. _N. A. F._, 2490.

In the former edition, this species was referred to _P. caespitosum_
Schw., of which the original description is as follows: "_P.
caespitosum_ L. v. S., pulcherrimum. In foliis et stipitibus
Rhododendri, Bethlehem. Physarum substipitatum aut saltem basi
attenuata, caespitosim crescens et sparsim. Caespitulis 3 linearibus;
peridiis stipatis, turbinatis, ovatis, basi contracta membranula
exterori luteosquamulosa aut punctato-squarrulosa. Sporidiis
nigro-brunneis, floccis citrinis inspersis." _Synopsis N. A. Fungi_,
2301.

The type from the Schweinitz herbarium is no longer in evidence. Without
it, the reference cannot be sustained.

Not uncommon in the eastern United States; reported also from Japan.

45. PHYSARUM ALBESCENS _Ellis._

PLATE XVI., Figs. 4, 4 _a_.

1889. _Physarum albescens_ Ellis _in litt_: not