concur, were the thing possible! But _Physarum connatum_ is already
a synonym twice over.[25] Unless we are done with the rules entirely,
_P. connatum_ cannot stand. _P. polymorphum_ and _P. leucophaeum_ are
names already in use, of course; and so under the circumstances, much as
it is to be regretted, there would seem nothing left to do but to cancel
all past synonymy and impose a new name whose permanence may at least be
hoped for, if not expected.

40. PHYSARUM TROPICALE _Macbr._

1899. _Physarum tropicale_ Macbr., _N. A. S._, p. 45.

PLATE XV., Figs. 4, 4 _a_, 4 _b_.

Sporangia scattered, gregarious, turbinate, short stipitate, blue-gray,
about 1 mm. in diameter; peridium above iridescent, green, blue, etc.,
dotted with minute flecks of white, below limeless, purple or bronze
shading to the brown of the stipe; stipe short, stout, slightly rugose,
cylindric, non-calcareous, brown; columella none; hypothallus none;
capillitium abundant, the nodes generally calcareous, small, uniform,
angular, white, uniformly distributed; spore-mass, black; spores dark
violet-brown, distinctly and closely warted, 12-15 mu.

A large handsome species recognizable by the peculiar turbinate
sporangium, with its iridescent peridial wall in which green strongly
predominates above, bronze below. The distinction between the upper and
lower peridium would suggest _Craterium_, but the internal structure is
not at all _Craterium_-like. The capillitium is typically of _Physarum_.
The color suggests _P. leucophaeum violascens_ Rost. From this species
it is at once distinguished by its much longer sporangia, larger and
rougher spores.

Mexico; _C. L. Smith_: Sure to be again collected once that unhappy
country shall again open its forests to research.

41. PHYSARUM NICARAGUENSE _Macbr._

PLATE XV., Figs. 7, 7 _a_, 7 _b_; XVII., 11 and 11 _a_.

1893. _Physarum nicaraguense_ Macbr., _Bull. Lab. Nat. Hist. Iowa_,
II., p. 383.
1894. _Physarum compressum_ Alb. & Schw., List., _Mycetozoa_, p. 53,
in part.
1910. _Physarum nicaraguense_ Macbr., Petch, _Mycetozoa Ceylon_,
p. 334.
1911. _Physarum reniforme_ List., _Mycetozoa, 2nd ed._, p. 72,
in part.

Sporangia multilobate or compound-contorted, below obconic, gray, ribbed
with calcareous thickenings; stem short, fuscous, longitudinally
wrinkled; hypothallus distinct, black; columella none, although the lime
massed at the centre of eac