The North American Slime-Moulds Part 55

1797. _Cribraria tenella_ Schrad., _Nov. Gen. Pl._, p. 6.

Sporangia gregarious, small, .3-.5 mm. in diameter or smaller, olivaceous or ochraceous, long-stipitate, nodding; stipe slender, dark brown or blackish, very long, reaching 6 mm., weak and flexuous; calyculus variable, sometimes well defined, brown, costate, sometimes represented by the costae only connected by a thin, transparent membrane; net well differentiated, the meshes small, irregular, the nodes small, black, more or less globular, prominent, connected by transparent threads with occasional or a few free ends; spores in ma.s.s, olivaceous-ochraceous, under the lens pallid, globose, smooth, 5-7 .

Very common eastward and south, on the weathered surface of rotten wood.

Generally easily recognized by its very long stipe, small, globose sporangium dotted with numerous small roundish nodules projecting plainly above the general surface. The obconic calyculus is always represented in the outline if not in definite structure.

New England, New York, Pennsylvania, Ohio, Tennessee, Illinois, Missouri, Iowa, Canada; Toronto,--_Miss Currie._

11. CRIBRARIA MICROCARPA (_Schrad._) _Persoon._

PLATE XVII., Fig. 4.

1797. _Dictydium microcarpum_ Schrad., _Nov. Gen. Pl._, p. 13.

1801. _Cribraria microcarpa_ Schrad., Pers., _Syn._, p. 190.

1875. _Cribraria microcarpa_ (Schrad.) Rost., _Mon._, p. 235.

1892. _Cribraria microcarpa_ Schrad., Ma.s.see, _Mon._, p. 63.

1893. _Cribraria microcarpa_ Schrad., Morg., _Myx. Mi. Vall._, p. 15.

1899. _Cribraria microcarpa_ Schrad., Macbr., _N. A. S._, p. 168.

1911. _Cribraria microcarpa_ Pers., Lister, _Mycetozoa, 2nd ed._, p. 183 (?).

Sporangia loosely gregarious, very small, .2-.3 mm. in diameter, yellow ochraceous, stipitate, nodding; stipe comparatively stout, dark brown or blackish, tapering upward, often twisted at the apex as in _D.

cancellatum_; calyculus none, represented by simple ribs which give off at intervals free or floating branchlets before blending into the common net; net well developed, the meshes large, the nodes small, irregular, though often rounded and prominent, black, connected by delicate transparent threads, with free ends few or none; spore-ma.s.s yellow, fading to ochraceous; spores pale, smooth, globose, 6-7 .

This species resembles at first sight the preceding, and has been often mistaken for it. As a matter of fact, the distinctions are generally very sharp. In the first place, the sporangia, when carefully measured, are seen to be not more than half as great in diameter; the meshes of the net, on the other hand, are much wider, the whole structure more compact. The nodules are like those of _tenella_, but are much fewer.

The stipe is shorter, the cup wanting, and the costae are few and simple.

The color suggests _C. aurantiaca_. The habitat and distribution as _C.

tenella_.

To anyone who will read the account of the species as given by the English _Mon., 2nd ed._, p. 183, it is immediately apparent that the author has in mind a different form from that seen and described in our territory and previously noted by the authors of Europe. These from Schrader down, agree in portraying a brunescent form with yellow spores; Mr. Lister enters it with the cyanic series and so describes and figures it throughout. Schrader figures a nut-brown species; Rostafinski uses that descriptive term in connection with the general appearance when fresh, but gives the spore-ma.s.s yellow; only in the stipe does he find another tint, nut-brown-purple. The figure, 145 in the _Monograph_ now before us portrays, except in color, our _C. tenella_ exactly. Dr. Rex, _Bot. Gaz._, XIX., 398, compares the present species with _C.

minutissima_, and _C. tenella_ with _C. dictydioides_; which is correct for the American presentation of the species named. _C. dictydioides_ is certainly our presentation of _C. intricata_, a geographic species at the least; but if _C. microcarpa_ is purple we have of it no representation; our forms under that name are closely related to _C.

tenella_, a yellow-spored species, and might perhaps be there referred; have, however, somewhat larger spores.

12. CRIBRARIA VIOLACEA _Rex._

PLATE XVII., Fig. 8.

1891. _Cribraria violacea_ Rex, _Proc. Phil. Acad._, p. 393.

Sporangia scattered or gregarious, very small, .2 mm. in diameter, violet tinted, erect, stipitate short, about one-half the total height, concolorous, slender, tapering upward; calyculus crateriform, persistent, or marked with minute plasmodic granules; the net rudimentary or poorly developed, the meshes large, irregular, the nodules also large triangular, violaceous; spores pale violet in ma.s.s, by transmitted light reddish, 7-8 , minutely warted.

A very minute but well-marked species discovered by Dr. Rex in Wissahickon Park, near Philadelphia, otherwise very rare. Lister, however, reports it from England. In minuteness to be compared with _C.

minutissima_, from which its color instantly distinguishes it. Dr. Rex reports the plasmodium as "violet black." All our specimens are on very rotten wood, ba.s.swood, _Tilia americana_.

Pennsylvania, Illinois, Iowa.

13. CRIBRARIA PURPUREA _Schrad._

1797. _Cribraria purpurea_ Schrad., _Nov. Gen. Pl._, p. 8.

Sporangia gregarious, large, 1 mm. in diameter, dark purple, erect, stipitate, depressed-globose; stipe concolorous, furrowed, about twice the diameter of the sporangium in length, with a distinct hypothallus; calyculus persistent, less than half the sporangium, obscurely ribbed, marked by concentric plications, the margin toothed; the net poorly differentiated, the meshes irregular in form and size, as are also the flat, unthickened nodes, the threads pale, free ends short and not numerous; spore-ma.s.s purple; spores by transmitted light, pale or colorless, 5-6 , smooth.

Rare. Found on rotten coniferous wood in deep forests. Easily recognized by its large size and uniform purple color. To the next species it offers a general resemblance, but has larger sporangia and an entirely different net. The plasmodium just before the formation of the fruit is scarlet.

Maine, New York, Pennsylvania, Ontario, Oregon, Colorado.

14. CRIBRARIA ELEGANS _Berk. & C._

1873. _Cribraria elegans_ Berk. & Curt., _Grev._, II., p. 67.

Sporangia gregarious, erect or nodding, small, .4-.5 mm., bright purple, stipitate; stipe long, slender, tapering upward, almost black, arising from a scanty hypothallus; calyculus about half the sporangium, finely ribbed, covered especially above with small purple granules, the margin toothed or perforate; net well developed, the meshes small, polygonal, the threads delicate, colorless, with many free ends, the nodules dark-colored, numerous and somewhat prominent; spore-ma.s.s pale purple; spores by transmitted light pale violaceous, smooth, 6-6.5 .

To be compared with the preceding. The small-meshed net with well-defined, dark-colored nodules is distinctive, aside from the fact of the much smaller sporangia. The stipe is also different, more slender, smooth, and dark-colored. The habitat of the two species appears to be the same. The present species is much more common, ranges farther west, and is to be looked for on the Pacific coast.

New York, Pennsylvania, South Carolina, Missouri, Iowa; Black Hills, South Dakota.

15. CRIBRARIA LANGUESCENS _Rex._

1891. _Cribraria languescens_ Rex, _Proc. Phil. Acad._, p. 394.

Sporangia scattered, very minute, .25-.35 mm., spherical, long-stipitate, drooping; stipe 2.5-3 mm., slender, flexuous, subulate, rugulose; calyculus about one-third the sporangium, reddish brown, s.h.i.+ning, minutely striate with granular lines, the margin more or less regularly serrate; net reddish brown, the meshes triangular and the threads simple, the nodes large, polygonal, flat, but well differentiated; the spores when fresh dull red in ma.s.s, paling with age; by transmitted light colorless, 6 , smooth.

A very singular species, easily recognizable by its long, slender stipes, terminating in exceedingly small spherical sporangia. The colors are obscure, but the striations on the calyculus are violet-tinted, and the reds perhaps predominate elsewhere. "In its scattered and solitary growth, its tall, slender stipes, and relaxed habit it resembles _C.

microcarpa_, in its network it approaches _C. tenella_, and its spores have the color of the paler form of _C. purpurea_." So Dr. Rex, _l. c._ Western forms of the first-named species have much shorter stipes; the network in the specimens before us is unlike that of _C. tenella_, but resembles that of _C. purpurea_.

Rare, on very rotten wood, in the forest. New York, Ohio, South Carolina, Ontario.

16. CRIBRARIA CUPREA _Morgan._

PLATE XVII., Fig. 7.

1893. _Cribraria cuprea_ Morg., _Jour. Cin. Soc_., p. 16.

Sporangium very small, .33 mm., oval or somewhat obvoid, copper-colored, stipitate, nodding; stipe concolorous or darker below, subulate, curved at the apex, 2-4 times the sporangium; calyculus about one-half the sporangium, finely ribbed and granulose within, the margin nearly even; the net rather rudimentary, the meshes large, triangular or quadrilateral, the nodules also large, flat, concolorous, the threads slender, transparent, with free ends few; spores in ma.s.s copper-colored, by transmitted light colorless, smooth, 6-7 .

Recognizable by its small size and peculiar color, that of bright copper, although this fades somewhat with age, and the metallic tints are then lacking. Related to the preceding and in specimens having globular sporangia closely resembling it; but the ground color in _C.

languescens_ is always darker, and the stipe proportionally much longer.

In habit the sporangia are widely scattered, much more than is common in the species of this genus. Miss Lister, _2nd ed._ regards this as a var.

of No. 15.

Comparatively rare. Before us is one very small colony of sporangia from Iowa, one from Ohio, and a large number from Missouri. If one may judge from the material at hand, the favorite habitat is very rotten ba.s.swood, _Tilia americana_.