The North American Slime-Moulds Part 62

Maine to the Black Hills and Colorado, and north and west; Alaska to Nicaragua.

9. ARCYRIA CINEREA (_Bull._) _Pers._

PLATE II., Figs. 3, 3 _a_.

1791. _Trichia cinerea_ Bull., _Champ. de France_, p. 120, Tab. 477, Fig. iii.

1801. _Arcyria cinerea_ (Bull.) Pers., _Syn. Fung._, p. 184.

Sporangia scattered or gregarious, ovoid or cylindrical, generally tapering upward, about 2-3 mm. high, ashen gray, sometimes with a yellowish tinge, stipitate; calyculus very small, thin; stipe about half the total height, rising from a small hypothallus, thin, gray or blackish, densely crowded with spore-like cells; capillitium dense, freely branching, ashen, or yellowish, little wider below, minutely spinulose; spore-ma.s.s concolorous, spores by transmitted light colorless, smooth, 6-7 .

A very common little species, easily recognized by its color and habit.

The capillitium is more dense than in any other species and expands less. The stipe is about equal to the expanded capillitium, unusually long. The plasmodium occurs in rotten wood, especially species of _Tilia_, is gray and, judging from the number of sporangia found in one place, scanty.

Bulliard, _l. c._, gives the first account of the species by which it can with any certainty be identified. By some authors _Clathrus recut.i.tus_ Linn. is cited as a synonym. We fail to distinguish _A.

cookei_ Ma.s.s. from the old type.

Widely distributed; Maine to Alaska, and south to Mexico and Nicaragua.

10. ARCYRIA DIGITATA (_Schw._) _Rost._

1831. _Stemonitis digitata_ Schw., _N. A. F._, p. 260, No. 2350.

1868. _Arcyria bicolor_ Berk. & C., _Jour. Linn. Soc._, X., p. 349.

1875. _Arcyria digitata_ (Schw.) Rost., _Mon._, p. 274.

Sporangia compound, that is gathered in tufts, number 3-12 or more on a single stipe, the cl.u.s.ters themselves scattered; individual sporangia elongate cylindric, about 3-4 mm. long, ashen gray or nearly white, stipitate; stipe as long or longer than the sporangium, stout, sometimes showing traces of consolidation of several, sometimes none, dark brown or black; capillitium looser and more expanded than in the last, the threads more strongly spinulose; spore-ma.s.s concolorous, spores under the lens colorless, smooth, globose, 7.5-8

Closely related to the preceding, but different in habit and on the whole larger and more robust throughout. The stipes in some cases are completely merged in one; in others traces of coalescence remain. The number of united sporangia varies. There are some cl.u.s.ters before us containing 16 and 18 in a single fascicle!

Not very common. On rotten wood of deciduous trees, especially south.

New England, Pennsylvania, Ohio; Black Hills, South Dakota, and south to Nicaragua.

_Arcyria bicolor_ Berk. & C. seems to refer to the fact that the sporangia have sometimes an ochraceous tint. Berkeley's specimens are from Cuba. Our latest specimens are from Nicaragua; the form seems not to be reported from the old world.

11. ARCYRIA POMIFORMIS (_Leers_) _Rost._

1775. _Mucor pomiformis_ Leers, _Flor. Herb._, p. 218.

1875. _Arcyria pomiformis_ Rost., _Mon._, p. 271.

Sporangia scattered, gregarious, globose, bright yellow, very minute, .5 mm. high, .3 mm. in diameter, stipitate; stipe short, one-third the total height, pale brown or yellow; hypothallus none; capillitium loose, freely expanding, not deciduous, honey-yellow, the threads generally wide, 4-5 , toward the periphery more narrow, 2.5 warted, marked with blunt spinules, which not infrequently pa.s.s into distinct transverse, narrow plates or half-rings, free ends clavate and numerous; spore-ma.s.s yellow, spores by transmitted light smooth, granular, globose, 7-9 .

This species as represented by the material before us seems constant in size, color, and microscopic characters, in all which it differs from all species here listed. It resembles somewhat _Lachn.o.bolus globosus_ Schw., but differs in habit, habitat, color, the capillitium, its attachment and in the mode of dehiscence. In the present species the wall is evanescent almost _in toto_; in _L. globosus_ is it remarkably persistent, and the capillitium is adherent.

Probably rare. Its smallness removes it from sight of all but the most exact collectors. Maine, New York, South Carolina, Alabama, Missouri, Iowa; Black Hills, South Dakota; Ontario;--_Miss Currie._

While usually remotely gregarious a collection from southern California shows that on occasion the entire plasmodium may pa.s.s to fruit with narrowest limits, forming a stipitate, compact, globose ma.s.s of crowded, superimposed sporangia as in _Oligonema nitens_. Set Plate XX., Fig. 12.

12. ARCYRIA INSIGNIS _Kalkbr. & Cke._

1882. _Arcyria insignis_ Kalkbr. & Cke., _Grev._, X., p. 143.

1911. _Arcyria insignis_ Kalkbr. & Cke., List., _Mycet., 2nd ed._, p. 240.

Sporangia gregarious or cl.u.s.tered, pale or bright rose-colored, .5-1.5 mm. in height, stipitate, ovate or cylindric; stipe short, .2-.4 mm.

red, with spore-like cells; capillitium a close net-work of delicate threads with a few bulbous free ends, with faint transverse bands or short spinules, or nearly smooth, colorless beneath the lens; spores colorless, nearly smooth, 6-8 .

Reported from Ma.s.s. by Miss Lister. Should follow No. 8: apparently a very delicate form of the common species, _A. denudata_.

=3. Heterotrichia= _Ma.s.s._

1892. _Heterotrichia_ Ma.s.s., _Mon._, p. 139.

Sporangia distinct, stipitate; the peridium simple evanescent above as in _Arcyria_; capillitium centrally attached, freely branched, the threads within very slender, without broad, anastomosing to form a dense peripheral network, and everywhere extended to form short, free, often hamate tips. A single species,--

1. HETEROTRICHIA GABRIELLAE (_Rav._) _Ma.s.s._

PLATE XIII., Figs. 1, 1 _a._

1850. _Arcyria gabriellae_ Rav. _in litt. ad Cooke_.

1892. _Heterotrichia gabriellae_ Ma.s.s., _Mon._, p. 140.

1911. _Arcyria ferruginea_ Saut., var. _heterotrichia_ List., _Mycet., 2nd ed._, p. 234.

Sporangia crowded or gregarious, oblong cylindric, ovoid, at first red, becoming yellowish brown, stipitate; the peridium evanscent except the calyculus, which is small and thin, polished; stipe shorter than the expanded capillitium, pale reddish brown; capillitium centrally attached, showing threads of two sorts, those within freely branching, slender, 1-1.5 , marked with half-rings or ridges, those on the periphery very different, yellow, broad, 5-6 , forming rather dense reticulations, with abundant free tips, acute and often curved, the whole surface here minutely and densely warted; spore-ma.s.s reddish yellow, spores by transmitted light colorless, globose, 7-8 .

The peculiar double capillitium seems to separate this form from the true arcyrias. Some difference in the diameter of the capillitial threads in different regions is not infrequent in the several species of _Arcyria_, but that difference is here emphasized and rendered yet more striking by the peculiar free tips. The present forms bear only the most superficial resemblance to _A. ferruginea_ Saut., with which species it is in some quarters sought to unite it.

Very rare. Collected, as noted, nearly fifty years ago in South Carolina by Ravenel, it was more recently (1896) again collected in Maine by the late Professor Harvey.

_D._ PROTOTRICHIACae

A single genus,--

=Prototrichia= _Rost._

1876. _Prototrichia_ Rost., _Mon. App._, p. 38.

A single species,--

1. PROTOTRICHIA METALLICA (_Berk._) _Ma.s.s._

PLATE XVIII., Figs. 12, 12 _a_, 12 _b_.