The North American Slime-Moulds Part 58

Sporangia gregarious, generally rounded or cushion-shaped, depressed, sessile, iridescent bronze, 1 mm. in diameter; peridium thin, translucent, opening irregularly; capillitium of simple threads, not netted, but often forked two or three times, taut, running from base to top; spores yellow, by transmitted light pale yellowish, minutely roughened, 8-10 .

This interesting species was collected in Orono, Maine, in 1889, by Professor F. L. Harvey, and so far as can be learned has not been taken since. Mr. Lister records two species from England which he refers to this genus. As to its systematic place, Dr. Rex says, _l. c._ "It stands as a single representative of a new and separate family adjoining the _Perichaenacae_ in the order _Calonemeae_ of Rostafinski."

Rare. Maine.

2. DIANEMA CORTICATUM _List._

PLATE XVI., Figs. 5 _a_, 5 _c_.

1894. _Dianema corticatum_ List., _Mycetozoa_, p. 205.

"Plasmodium pink"; sporangia sometimes flat-hemispheric, more often ill-defined, united in irregular, depressed, netted plasmodiocarps, generally dull brown; peridium opaque, didermatous, capillitium of simple or rarely branching filaments, variously beaded or marked with spiral bands, lightly attached at either end, occasionally twisted together; spore-ma.s.s dull brown, the spores in cl.u.s.ters of four or more, colorless by transmitted light, more or less verruculose, ellipsoidal, about 8-10 .

Our specimens are from the mountains of Alberta.

A curious, flat plasmodiocarp, an inch or more in length. It suggests _Hemitrichia serpula_ prematurely dry.

3. DIANEMA ANDERSONI, _Morg._

_Dianema andersoni_, _Morg._ MS., _non. pub._

Sporangium globose, sessile or sub-stipitate, seated on a thin brownish hypothallus; the wall a thin smooth pinkish membrane, when dry rugulose and iridescent, the inner surface somewhat thickened below and brownish at the base. Capillitium arising out of the thickened base, the threads hyaline or pinkish, ascending, flexuous, simple, or branched a time or two, the extremities attached on all sides to the wall of the sporangium. Spores globose, very minutely warted, pale, pinkish, 10-11 , in diameter, free.

Growing on 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 circ.u.mscissile 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-ma.s.s ochraceous yellow; spores by transmitted light pale yellow, minutely roughened, 10 .

Perhaps common, but seldom collected, probably overlooked on account of protective coloration; the color is about that of the habitat, the weathered surface of dead herbaceous stems and roots. On dead corn stalks not infrequent. Differs from other species of the genus in having smoother capillitium, for which reason Rostafinski calls the present species _Perichaena vermicularis_. _O. pallida_ Berk. & C. seems to us to be the same thing, _N. A. F._, 726.

New England, New Jersey, South Carolina, Ontario, Ohio, Iowa.

2. OPHIOTHECA CHRYSOSPERMA _Currey_.

1854. _Ophiotheca chrysosperma_ Currey, _Quart. Mic. Jour._, II., p. 240.

1875. _Cornuvia circ.u.mscissa_ (Wallr.) Rost., _Mon._, p. 290.

1911. _Perichaena chrysosperma_ Lister, _Mycetozoa, 2nd ed._, in part, p. 248.

Plasmodiocarp elongate, bent and curved in various ways, spherical, more rarely annular or even reticulate, yellowish or ochraceous brown, opening irregularly; peridium thin, with yellowish outer layer; capillitium rather abundant, of threads slender, sparingly branched and minutely but distinctly spinulose; spore-ma.s.s yellow, spores by transmitted light pale, almost smooth, about 8 .

Occurs on the inner bark of deciduous trees, especially of oak. Not common.

This is possibly _Cornuvia circ.u.mscissa_ (_Wallr._) of Rostafinski's monograph; but it is doubtful to what Wallroth referred. Rostafinski's other citations are equally uncertain. Currey's figures and description alone merit recognition.

Ohio, Iowa, Tennessee; Canada.

3. OPHIOTHECA WRIGHTII _Berk._

PLATE II., Figs. 7, 7 _a_, 7 _b_.

1868. _Ophiotheca wrightii_ Berk. & C., _Jour. Linn. Soc._, X., p. 349.

1876. _Cornuvia wrightii_ (Berk. & C.) Rost., _Mon. App._, p. 36.

1892. _Cornuvia wrightii_ (Berk. & C.) Macbr., _Bull. Lab. Nat.

Hist. Ia._, II., p. 122.

1911. _Perichaena chrysosperma_ Lister, _Mycetozoa, 2nd ed._, p. 248.