PLATE III., Figs. 4, 4 _a_, 4 _b_.

1772. _Mucor serpula_ Scop., _Fl. Carn_, II., p. 493.
1794. _Trichia serpula_ (Scop.) Pers., _Roem. N. Bot. Mag._, I., p. 90
1875. _Hemiarcyria serpula_ (Scop.) Rost., _Mon._, p. 266.

Fructification plasmodiocarpous, often covering several square
centimetres, terete, branching freely and usually everywhere reticulate,
rusty, tawny, or bright yellow; the peridium thin, transparent, with
irregular dehiscence; hypothallus none; capillitium variable, a tangle
of long yellow threads, sparingly branched, free everywhere, except
below, spinulose, the free tips spinose, acuminate, spiral ridges three
or four, with traces of longitudinal striae; spore-mass golden yellow,
spores beneath the lens pale yellow, globose, delicately reticulate,
about 10 mu.

Very common, recognized by its bright yellow color and conspicuous
reticulate habit. The plasmodium is yellow, at least upon emergence, and
passes almost without change to fruit. Found on rotten logs of every
description, on the _lower_ surface. In the Mississippi valley, the
lower surface of planks used in the construction of sidewalks appears to
be a favorite habitat.

Common west to the Rocky Mountains, south to Mexico and Nicaragua.

2. HEMITRICHIA KARSTENII (_Rost._) _List._

1876. _Hemiarcyria karstenii_ Rost., _Mon., App._, p. 41.
1891. _Hemiarcyria obscura_ Rex, _Proc. Phil. Acad._, p. 395.
1894. _Hemitrichia karstenii_ Lister, _Mycetozoa_, p. 178.

Fructification plasmodiocarpous, with a tendency to form distinct
sessile, globose sporangia, color brownish red; capillitium a sparingly
branched network, with free ends few, the thread marked by seven or
eight faint spirals, the interspaces narrow, dull red in color, and 2.5
mu in diameter; spores yellow, delicately warted, 10-10.5 mu.

This is doubtless a very rare species. In the description we have
followed Dr. Rex, _l. c._, as being more to the point for American
forms. It is not improbable that the American material may after all be
distinct, as discrepancies, if one may judge by descriptions, are not
few. Lister, who had a slide from Dr. Rex, considers the European and
American forms the same.

In outward appearing, plasmodiocarpous phases of this species very
closely resemble forms of _Licea_ or _Ophiotheca_, and are in
consequence often wrongly labeled.

Toronto; Montana--_Anderson_. To be looked for north and west.

3. HEMITRICHIA OVATA (_Pers._) _