angia x
90. One divested of the wall and showing the rigid capillitium. _c._
Capillitium and spores x 500.

[Illustration: The Journal of the Cin. Soc. Natural History.

VOL. XIX. PLATE XIV.

MORGAN ON MYXOMYCETES.]

_B. Sporangia sessile._

22. PHYSARUM PLUMBEUM, Fr. Sporangia small, globose or obovoid, sessile,
on a narrow base, gregarious, sometimes close but seldom confluent; the
wall a thin violaceous membrane, with a very thin layer of small white
scales and minute granules of lime, sometimes naked. Capillitium a loose
net-work of slender tubules, with slight expansions at the angles; the
nodules of lime white, numerous, more or less elongated, irregularly
lobed and branched. Spores globose, even, violaceous, 7-9 mic. in
diameter.

Growing on old leaves, sticks, etc. Sporangia .3-.4 mm. in diameter,
quite regular in shape, attached by a narrow base, sometimes by a mere
point, rarely confluent. The lime on the wall of the sporangium is
rather scanty, sometimes altogether absent, and the nodules of lime in
the capillitium are rather small. The species is figured by Micheli N.
P. G. Tab. 96, Fig. 9. It is named by Fries S. M., III, p. 142. It is
figured again by De Bary, _Die Mycetozoen_, Tafel I.

23. PHYSARUM ATRUM, Schw. Sporangia sessile, subglobose or oblong, by
confluence, more or less elongated, bent or flexuous and branched; the
wall a thin violaceous membrane, rugulose, covered by a wrinkled and
reticulate layer of white granules of lime, which sometimes become thin
or disappear. Capillitium a loose net-work of tubules, more or less
expanded at the angles; the nodules of lime white, numerous, large,
irregularly lobed and branched. Spores globose, very minutely warted,
violaceous, 8-10 mic. in diameter.

Growing on old leaves, bark, grasses, etc.; apparently the most common
of these three cinereous species. Sporangia .3-.5 mm. in thickness, some
of them roundish or oblong, others elongated to several millimeters. The
sporangium is often elegantly reticulate as observed by Schweinitz even
when the lime is quite scanty. In Saccardo's _Sylloge_ Berlese changed
the name to _Physarum reticulatum_, but this is unnecessary, as the
_Physarum atrum_ of Fries is not a Myxomyces.

24. PHYSARUM CINEREUM, Batsch. Sporangia large, subglobose, sessile,
gregarious, sometimes close and confluent; the wall a thin violaceous
membrane, with a closely adherent layer of minute gra