ness and named by Phillips who received it in England,
_badhamia inaurata_. He seems not to have described it. Since its first
appearance, the form has been found repeatedly in the Juras. Specimens
are before me from Mt. Rainier believed to be the same. The
plasmodiocarpous habit and yellow capillitium separate this from related
_P. contextum_ and _P. mortoni_.

Europe, California, Washington.

8. PHYSARUM DIDERMA _Rost._

PLATE XVIII., Fig. 9.

1875. _Physarum diderma_ Rost., _Mon._, p. 110.
1898. _Physarum didermoides_ var. _lividum_ List., _Jour. Bot._,
XXXVI., p. 162.
1899. _Physarum diderma_ Rost., Macbr., _N. A. S._, p. 30.
1911. _Physarum testaceum_ Sturgis, List., _Mycetozoa, 2nd ed._,
p. 79.

Sporangia snow-white, clustered, sessile or narrowly adnate, globose or
polygonal by mutual compression; peridium double, the outer dense,
fragile, thick, calcareous, the inner delicate, remote, translucent,
capillitium well developed, the calcareous nodules white, rounded or
angular, sometimes uniting to form a pseudo-columella; spore-mass black;
spores purplish, distinctly rough, 10-12 mu.

A beautiful and distinct species. As others in the group with which it
is here associated, it is a physarum with the outward seeming of a
diderma. It occurs in Europe, therefore it is safe to assume that
Rostafinski saw it. So well marked it is that any good description will
define it, and Rostafinski describes it perfectly, adequately.[23]

Mr. Lister having used for another species the name we here apply--see
under _P. bitectum_--referred this present form to _P. didermoides_
Rost., _l. c._ Professor Sturgis, convinced that such reference was at
least doubtful, gave to our American gatherings the distinctive name
above, citing specimens from Massachusetts, from Colorado, and from
California. Curiously enough he also includes specimens of _R.
didermoides_ var. _lividum_ List., sent from England!

Rare! Certainly rare in Europe and so far seldom seen in the United
States, though widely distributed. Specimens are before us from Ohio,
Michigan, Iowa, Oregon. No doubt the mountains of the north Pacific
coast, a region to-day almost unsearched, will yet afford the species in
abundance.

As stated Mr. Lister first applied the name _P. diderma_ to a
plasmodiocarpous form occurring in England and near _P. sinuosum_. More
lately, _Mon., 2nd ed._, p. 78, he adopts a new specific name, _P.
bitectum_