for the English specimens, and enters _P. diderma_ as a
probable synonym for _P. lividum_ R. Evidently our present form as
described above has not come to Mr. Lister's view. He says the original
type is not to be consulted.

There is really no more merit in this later comparison than in that
discarded. The species _P. diderma_ is not _P. lividum_, but stands as
originally delimited, and will, doubtless, some day yet again appear in
its own behalf upon the witness-stand of time; when, as before, a
Frenchman in DeBary's old-time haunts may rise to give it welcome,
brought back by some keen-eyed Polish student eager now in the arts of
peace, from Warsaw's shady groves.

9. PHYSARUM CONTEXTUM _Persoon._

PLATE IX., Figs. 3 and 3_a_.

1796. _Diderma contextum_ Persoon, _Obs. Myc._, I., p. 89.
1801. _Physarum contextum_ Persoon, _Syn. Meth._, p. 168.
1829. _Diderma contextum_ Persoon, Fries, _Syst. Myc._, III., p. 111.
1873. _Diderma ochroleucum_ Berk. & C., _Grev._, II., p. 52.
1879. _Diderma flavidum_ Pk., _N. Y. Rep. State Mus._, XXXI., p. 55.

Sporangia distinct, sessile, densely crowded, sub-rotund reniform more
often elongate, interwoven; peridium double; the outer rather thick,
calcareous, yellow, or yellowish white, the inner thin, yellowish;
capillitium white, containing numerous large, irregular calcareous
granules; columella none; spores deep violet, 11-13 mu, covered with
minute spinules.

This singular species occurs not rarely upon the bark of fallen twigs,
upon bits of straw or grass-stems lying undisturbed upon the ground. In
such a position the slime-mould covers, as with a sheath, the entire
substratum. The outer peridium, especially its upper part, is entirely
evanescent, our Fig. 3 shows the sporangia with upper outer peridium
wanting. Not rare in summer and autumn.

New England, New York, Pennsylvania, Ohio, Wisconsin, Illinois, Iowa,
Colorado, Oregon, Nicaragua.

10. PHYSARUM CONGLOMERATUM (_Fr._) _Rost._

1803. _Spumaria granulata_ Schum., _Enum. Pl. Saell._, II., p. 196,
No. 1419.
1803. _Spumaria minuta_ Schum., _l. c._
1829. _Diderma granulatum_ Schum., Fries, _S. M._, III., p. 110.
1829. _Diderma minutum_ Schum., Fries, _l. c._, p. 111.
1829. _Diderma conglomeratum_ Fries, _l. c._, p. 111.
1875. _Physarum conglomeratum_ (Fr.) Rost., _Mon._, p. 108.
1892. _Physarum rostafinskii_ Massee, _Mon._, p. 301.
1894. _Physarum conglomeratum_ Rost., Lister