old wood and bark of _Alnus_; British Columbia, _W. B.
Anderson_.

Sporangium spherical, 6-8 mm. in diameter, sessile or on a very short
stipe. This species differs from D. harveyi Rex in the _uniform pinkish_
color of the wall and of the spores; the dividing threads are furnished
remotely with minute roundish tubercles as in _Didymium_; the spores are
somewhat larger than in _D. harveyi_.

_B._ PERICHAENACEAE

=Key to the Genera of the Perichaenaceae=

_A._ Sporangia more or less plasmodiocarpous in type,
terete; dehiscence irregular 1. OPHIOTHECA

_B._ Sporangia more or less polygonal in outline, or
round, depressed; dehiscence circumscissile 2. PERICHAENA

=1. Ophiotheca= _Currey_.

1869. _Ophiotheca pallida_ Berk. & C., _Jour. Linn. Soc._, X., p. 350.

Fructification generally plasmodiocarpous, terete, bent or flexuous,
often annular or cornuate, rarely globose, opening irregularly, peridium
thin, not polished, covered more or less strongly with a distinct layer
of scales or granules; capillitium of slender, loosely branching
filaments, the surface rough to strongly spinulose; spores yellow.

As a generic name _Ophiotheca_ plainly has priority. _Cornuvia_ as
understood by Rostafinski has no representative so far in our region.

=Key to the Species of Ophiotheca=

_A._ Plasmodiocarp usually upon herbaceous stems,
slender 1. _O. vermicularis_

_B._ Plasmodiocarp on rotting bark, logs, etc,

_a._ Pale brownish or yellowish 2. _O. chrysosperma_

_b._ Chestnut brown or blackish 3. _O. wrightii_

1. OPHIOTHECA VERMICULARIS (_Schw._) _Macbr._

1834. _Physarum vermicularis_ Schw., _N. A. F._, No. 2296.
1869. _Ophiotheca pallida_ Berk. & C., _Jour. Lin. Soc._, X., p. 350.
1873. _Ophiotheca umbrina_ Berk. & C. Grev., II., p. 88.
1876. _Perichaena pallida_ (Schw.) Rost., _Mon. App._, p. 34.

Plasmodiocarp very slender, terete, elongate, flexuous or reticulate,
annular, etc., of dull gray or neutral tint; the peridium thin,
translucent, but with a delicate granular outer coating; capillitium of
slender threads, frequently branched, warted and usually minutely
spinulose; spore-mass ochraceous yellow; spores by transmitted light
pale yellow, minutely roughened, 10 mu.

Perhaps common, but seldom collected, probably overlooked on account of
protective c