on, especially on rotten oak logs. Easily recognized by the
peculiar form of the fruit, spherical before dehiscence, floriform
after. Unlike most species, this form often fruits in dark places, in
the interior of a log, even in the ground.

New England, Ontario to Iowa and Nebraska, and south.

19. DIDERMA RUGOSUM (_Rex_) _Macbr._

PLATE XVIII., Fig. 10.

1893. _Chondrioderma rugosum_ Rex, _Proc. Phil. Acad._, p. 369.

Sporangia gregarious, scattered, white or ashen, rugulose over the whole
surface, the ridges marking the lines of subsequent rupture or
dehiscence, the peridium thin papyraceous, stipitate; stipe well
developed about equal to the sporangium, subulate, almost black;
hypothallus none; columella distinct, generally white, sometimes small,
globose, sometimes penetrating the sporangium, to one-half the height;
capillitium white or colorless, the filaments freely forked and combined
by lateral branches into a loose network attached to the columella and
basal wall below and the upper sporangial wall above; spores
violaceous-brown, warted, 8-10 mu.

This species is well designated _rugosum_, and is recognizable at sight
by its wrinkled, areolate surface. Related to _D. radiatum_ in the
prefigured dehiscence, but otherwise very distinct. Liable to be
overlooked as a prematurely dried physarum. Rare. Plasmodium gray.

North Carolina, Iowa.

=4. Lepidoderma= _DeBary_

1858. _Lepidoderma_ DeBy., MS. Rost., _Versuch_, p. 13.

Sporangia stalked or sessile; peridium cartilaginous, adorned without
with large calcareous scales, superficial or shut in lenticular
cavities; capillitium non-calcareous.[33]

=Key to Species of Lepidoderma=

_A._ Sporangia stipitate, stipe brown 1. _L. tigrinum_

_B._ Sporangia sessile, plasmodiocarpous,
spores 10-12 mu 2. _L. carestianum_

_C._ Sporangia plasmodiocarpous, spores 8-10 mu 3. _L. chailletii_

1. LEPIDODERMA TIGRINUM (_Schrad._) _Rost._

PLATE XIV., Fig. 7.

1797. _Didymium tigrinum_ Schrad., _Nov. Gen. Plantarum_, p. 22.
1873. _Lepidoderma tigrinum_ (Schrad.) Rost., _Versuch_, p. 13.

Sporangia scattered, rather large, hemispherical-depressed, stipitate,
umbilicate beneath, the peridium shining, olivaceous or purplish, tough,
covered more or less abundantly with angular scales; the stipe stout,
furrowed, dark brown, but containing calcareous deposits withal,
tapering upward,