Chapter VII: Section II: Tilmadoche (2)

Sporangia scattered or gregarious, very small, .3-.4 mm., dull gray, thin-walled, dotted with minute, white calcareous granules, stipitate; stipe long, about 2 mm., stout, attenuated upward, striate longitudinally or wrinkled, filled with irregular yellow masses of lime and accordingly bright yellow in color; columella none; capillitium forming a dense net, with comparatively small yellow nodular thickenings; spores globose, purplish, each minutely papillose and displaying several scattered spots occasioned by local development of the papillae; diameter of the spores 9-10 mu.

This species was set up for the reception of certain material collected by Professor Shimek, in 1892, in Nicaragua. It remains so far unique. The small globose sporangium mounted upon a long upwardly tapering stipe, .5 mm. thick below, but narrowed at the extreme base where it is lightly attached, a stem which is simply a sack stuffed with yellow lime-granules;--this and the yellow capillitium are distinguishing features. The capillitium and spores suggest _Tilmadoche viride_, but the entire habit precludes such reference. Perhaps nearest to _P. melleum_.

Castillo, Nicaragua.

Miss Lister thinks this the same as _P. tenerum_ Rex. But the whole habit and external appearance are different; the stipe notably long, clumsy, surcharged with lime; a very singular form.

36. PHYSARUM DIDERMOIDES (_Pers._) _Rost._

PLATE IX., Figs. 1, 1 _a_, 1 _b_, 1 _c_.

1801. _Spumaria (?) didermoides_ Acharius, Pers., _Syn. Fung._,
p. xxix.
1829. _Diderma oblongum_ Fr., _Syst. Myc._, III., p. 103.
1831. _Spumaria licheniformis_ Schw., _N. A. F._, p. 261, No. 2364.
1832. _Physarum atrum_ Schw., _Syn. Fung., Am. Bor._, p. 258.
1875. _Physarum lividum_, Schw., Rostafinski, _Mon._, p. 96.
1875. _Physarum didermoides_ (Ach.) Rost., _Mon._, p. 97.

Plasmodium pale, watery-white or gray; sporangia crowded, ovoid or cylindric, stipitate or sessile, blue-gray, often capped with white; stipe variable in length and structure, where well developed pure white, often flattened, expanded and diaphanous, connate with others through the irregular reticulate or sheet-like hypothallus; columella none; capillitium ample, the lime knots angular or rounded, white connected by hyaline threads; spores in mass black, by transmitted light dark violet, decidedly spinulose, 12-15 mu.

A very variable species in many particulars. The sporangia in the same cluster are stipitate and sessile, ovoid and spherical. Our description does not quite agree with that of Rostafinski. As may be seen from the plate, it is the _outer_ peridium that is with us white, burdened with lime, the inner is simpler and comparatively thin. The whiteness of the outer peridium is however, easily displaced. The colony may not show it at all, in which case the peridia remaining give to the fructification entire a pale lead color, very characteristic. The disposition of the lime in the capillitium is also notably variable. Specimens occur which in so far realize Rostafinski's _Crateriachea_; that is, the lime is massed as a snow-white pseudo-columella in the centre of each sporangium. In such cases the lime of the outer peridium is scant or limited in amount, never forming the calcareous cap shown in Fig. 1. The size of the spores is also variable. Rostafinski gives 12.5-14.2 mu; not infrequently a single spore reaches 16 mu, a very unusual range of variation.

The species is not common in the upper Mississippi valley, but can be obtained in quantity where once it appears, as the plasmodia are profuse.

Ohio, Carolinas, Tennessee, Iowa, South Dakota, Kansas. Especially to be looked for on the bark of fallen stems of _Populus_ and _Negundo_.

Brazil, India, Japan.

_Physarum lividum_ Rost., _Mon._, p. 95, is but a less calcareous form of this, as is evident even by the author's description. Professor Morgan thought _P. lividum_ a phase of _P. griseum_ Lk. Link, however, reckons _P. griseum_ the same as _P. cinereum_. Link, _Diss._, I., p. 27.

37. PHYSARUM LEUCOPUS _Link._

PLATE IX., Figs. 7, 7 _a_, 7 _b_.

1809. _Physarum leucopus_ Link, _Diss._, I, p. 27.

Sporangia gregarious, stipitate, globose snow-white, with a didymium like covering of calcareous particles; stipe white, not long, conical or tapering rapidly upward, slightly sulcate, brittle, from an evanescent hypothallus; columella none or small; capillitium, consisting of rather long hyaline threads, connecting the usual calcareous nodes, which are large, angular, snow-white; spore-mass black; spores by transmitted light, violet-brown, distinctly warted, about 10 mu.

The snow-white, nearly smooth stem, the small sporangium (1/2 mm.) covered with loose calcareous granules, distinguish this rare species. It looks like a small _Didymium squamulosum_. Fries called it _D. leucopus_, _Syst. Myc._, III., p. 121.

Rare. Iowa, Ohio, Maine; Portugal.

38. PHYSARUM COMPRESSUM _Alb. & Schw._

PLATE XVIII., Fig. 14, and PLATE XIX., Fig. 12 and Fig. 4.

1805. _Physarum compressum_ Alb. & Schw., _Fung. Lus._, p. 97.
1875. _Physarum nefroideum_ Rost., _Mon._, p. 93, in part.
1875. _Physarum affine_ Rost., _Mon._, p. 94.
1909. _Physarum compressum_ Alb. & Schw., Torrend, _Fl. des Myx._,
p. 197.
1911. _Physarum compressum_ List., _Mycetozoa, 2nd ed._, p. 70.

Sporangia more or less scattered, _compressed_-globose, or compressed-reniform, i. e. often umbilicate, stipitate, sessile, or elongate as if plasmodiocarpous, calcareous, white or ashen; peridium thin, covered with squamules, opening irregularly, usually by apical cleft; stipe, when present, short, stout, more or less sulcate, dark brown or ashen; capillitium a rather loose net, the nodules white, variable in size and shape; spores purplish-brown, delicately roughened, about 10-12.5 mu.

_P. affine_ R. was in this connection set up for European types compressed indeed, but more strongly _reniform_. The author says in his further description that the form _affine_ is less definitely umbilicate, has white stems, etc.; allantoid, one would now say. Such forms now begin to appear in America; and if for these a specific name is needed, it is provided, _P. affine_ Rost., Plate XIX., Fig. 4.

This seems to be a cosmopolitan species, now that we have found it. However, in North America it is rare. It is reported from Pennsylvania, from Colorado; Harkness found it in California, and the writer has often collected it in Oregon, on Mt. Rainier, Washington, and in California. Europe.

39. PHYSARUM NOTABILE _nom. nov._

PLATE IX., Figs. 2, 2 _a_, 2 _b_; PLATE XV., Fig. 2; and Frontispiece.

1873. _Didymium connatum_ Peck, _Rep. N. Y. Mus._, XXVI., p. 74.
1879. _Physarum polymorphum_ (Mont.) Rost., Peck, _Rep. N. Y. Mus._,
XXXI., p. 55.
1893. _Physarum leucophaeum_ Fr., Ellis, _N. A. F._, No. 2396,
_second exhibit_.
1893. _Physarum leucophaeum_ Fries, Macbr., _Bull. Lab. Nat. Hist.
Iowa_, II., p. 156.
1894. _Physarum compressum_ Alb. & Schw., List., _Mycetozoa_, p. 53,
in part.
1896. _Physarum connexum_ Link., Morg., _Jour. Cin. Soc._, p. 92,
in part.
1896. _Physarum confluens_ Pers., Morg., _l. c._, p. 94.
1899. _Physarum nefroideum_ Rost., Macbr., _N. A. S._, p. 41, in part.
1911. _Physarum connatum_ Lister, _Mycetozoa, 2nd ed._, p. 71.

Sporangia gregarious, sessile, stipitate, or even plasmodiocarpous; when stipitate, depressed, varying at times to irregular reniform in the same colony; globose, the peridium strongly calcareous, cinereous-white; stipe variable, generally tapering upward, always distinctly deeply plicate-furrowed throughout, in color dark, opaque, sometimes touched with white or gray; capillitium abundant, the white lime-knots, varying in size and shape, connected by rather long hyaline threads, with here and there an empty node; spore-mass black, by transmitted light, dark, sooty brown, minutely papillose, 10-11.5 mu.

This remarkable species, while not at all difficult of recognition to one familiar with its phases, is withal very difficult to define. Normally stipitate, it often shows from the same plasmodium all sorts of forms, the shape of the fructification dependent apparently upon external conditions prevalent at the time. The amount of calcium also varies, especially in the capillitium, where there is usually much, with a tendency to the formation of something like a pseudo-columella; the outer net in such cases nearly destitute. The calcium in the stipe also varies; the black or brown stipes are, of course, free from it; the gray or white, calcareous.

In this large and difficult genus, since spore-color is receiving increased consideration,--see No. 31 preceding,--it is proper to note that in the present case two types appear, one with spore-color under the lens, as described, the other with spores violaceous with no trace of black; unshadowed.

The preceding description is based on material assembled during forty years. The form is easily discoverable by any collector throughout the entire valley of the Mississippi and eastward to Nova Scotia. For its naming, students in America have vainly waited the decision of those having access to mycologic types in Europe. It seems now certain that the species is extremely rare in the old world if there occurrent; never seen by any of the earlier taxonomists including Fries and Rostafinski; perhaps adventitious in these later years, although thus far no specimen from Europe has reached this table.[24] _P. nefroideum_ of Strasburg herbarium turns out, after all, _teste_ Lister, to be _P. compressum_ Alb. & Schw., which accordingly shall now enjoy state and station of its own; our concern in European nomenclature, in the present instance, almost disappears, and we return to our synonymy from this side of the sea.

Mr. Lister would recur to Dr. Peck's _Didymium connatum_, which indeed represents the present species. In such disposition, how gladly would all concur, were the thing possible! But _Physarum connatum_ is already a synonym twice over.[25] Unless we are done with the rules entirely, _P. connatum_ cannot stand. _P. polymorphum_ and _P. leucophaeum_ are names already in use, of course; and so under the circumstances, much as it is to be regretted, there would seem nothing left to do but to cancel all past synonymy and impose a new name whose permanence may at least be hoped for, if not expected.

40. PHYSARUM TROPICALE _Macbr._

1899. _Physarum tropicale_ Macbr., _N. A. S._, p. 45.

PLATE XV., Figs. 4, 4 _a_, 4 _b_.

Sporangia scattered, gregarious, turbinate, short stipitate, blue-gray, about 1 mm. in diameter; peridium above iridescent, green, blue, etc., dotted with minute flecks of white, below limeless, purple or bronze shading to the brown of the stipe; stipe short, stout, slightly rugose, cylindric, non-calcareous, brown; columella none; hypothallus none; capillitium abundant, the nodes generally calcareous, small, uniform, angular, white, uniformly distributed; spore-mass, black; spores dark violet-brown, distinctly and closely warted, 12-15 mu.

A large handsome species recognizable by the peculiar turbinate sporangium, with its iridescent peridial wall in which green strongly predominates above, bronze below. The distinction between the upper and lower peridium would suggest _Craterium_, but the internal structure is not at all _Craterium_-like. The capillitium is typically of _Physarum_. The color suggests _P. leucophaeum violascens_ Rost. From this species it is at once distinguished by its much longer sporangia, larger and rougher spores.

Mexico; _C. L. Smith_: Sure to be again collected once that unhappy country shall again open its forests to research.

41. PHYSARUM NICARAGUENSE _Macbr._

PLATE XV., Figs. 7, 7 _a_, 7 _b_; XVII., 11 and 11 _a_.

1893. _Physarum nicaraguense_ Macbr., _Bull. Lab. Nat. Hist. Iowa_,
II., p. 383.
1894. _Physarum compressum_ Alb. & Schw., List., _Mycetozoa_, p. 53,
in part.
1910. _Physarum nicaraguense_ Macbr., Petch, _Mycetozoa Ceylon_,
p. 334.
1911. _Physarum reniforme_ List., _Mycetozoa, 2nd ed._, p. 72,
in part.

Sporangia multilobate or compound-contorted, below obconic, gray, ribbed with calcareous thickenings; stem short, fuscous, longitudinally wrinkled; hypothallus distinct, black; columella none, although the lime massed at the centre of each sporangium simulates one; capillitium white, densely calcareous, with heavy angular nodules connected with comparatively short threads; spores violet, globose, spinulose, about 12 mu in diameter.

Ometepe, Nicaragua. _Professor B. Shimek_.

This species resembles in some particulars No. 39, especially in the amount of lime present in both capillitium and peridium, in the fluted, sooty stipe, and the rough spores. Mr. Lister once regarded it as the same. Nevertheless, it differs from _P. notabile_ in many definite particulars. In the first place, the sporangia are different in form and habit. They are obconic, nearly always compound, convolute, or botryoid, in this respect somewhat resembling _P. polycephalum_. Besides, the sporangia are uniformly much smaller, and show constantly the strongly calcified centre, much transcending anything seen in _P. notabile_. The stipe also is peculiar, quite short, an upward extension or sweep of the common hypothallus which is usually very distinct or prominent; and, while the stipe is longitudinally wrinkled, it is much less so than in the related species, and in a different way. The spores are about the same in size, but differ in color, in this respect agreeing rather with _P. leucophaeum_.

In the _Mycetozoa, 2nd ed., l. c._, the present species is entered as a synonym of two described by Massee: _Tilmadoche reniformis_ Mass., Mon., p. 336, and _Didymium echinosporum_ Mass., _Mon._ 239. But Massee's description of his tilmadoche is, naturally enough, at variance in every important point with the facts in the species before us. Massee says: "... sporangia deeply umbilicate _below_, sausage-shaped and curved; the stem elongated slender erect, pale brown; capillitial nodes scattered, fusiform, colorless or yellow; spores 16-17 mu." It is evident that whatever Massee may have had in hand as he wrote it was _not P. nicaraguense_, which has spores 10-12 mu and reverses the remaining description.

But _Didymium echinosporum_ also defines _T. reniformis_ since Lister, _Mon._, p. 54, says they are based on two gatherings of one species. Of this second species Massee says: "A superficial resemblance to _T. nutans_, but distinct in the capillitium which contains _no trace of lime_; spores 12-14 mu!" Again it is evident that whatever Massee had in hand when he wrote, it was not _P. nicaraguense_ which "has capillitium almost Badhamia-like," i. e., burdened with lime!

Worse than all; Mr. Massee's _alleged_ types are in evidence; one labelled _P. reniforme_[26] includes forms of _P. didermoides_ and of _P. nicaraguense_; the other labelled by Berkeley _P. nutans_ is _P. nicaraguense_. So Mr. T. Petch, _Mycet. Ceyl._, who enters our species as from Ceylon, and the names cited from Berkeley, Massee, and others, as synonyms. He remarks, "Probably Thwaites' 135 and 55 were mixed during examination"! Doubtless! and some other things too! What Massee did have beneath his lens, no one now may say but apparently not in either case cited, the physarum of Central America.

42. PHYSARUM SULPHUREUM _Alb. & Schw._

1805. _Physarum sulphureum_ Alb. & Schw., _Consp. Fung._, p. 93,
Tab. VI, f. 1.
1818. _Physarum flavum_ Fries, _Symb. Gast._, p. 22.
1875. _Physarum sulphureum_ Alb. & Schw., Rost., _Mon._, p. 101.[27]

Sporangia gregarious, sub-globose, rugulose-squamulose, .6-.8 mm., sulphur-yellow, stipitate; peridium membranous, covered with calcareous scales; stipe stout, white, charged with lime, furrowed; columella none; capillitium strongly calcareous, the nodules large, white; spores violaceous, rough, 9-11 mu.

Northern Europe. (Lusatia) Lausitz, Alb. & Schw.; dim old Wendish region on the south borders of Brandenburg. Reported also from Sweden.

The description and figure given by Schweinitz, 1805, _l. c._, leave no doubt as to what he had in hand. Twenty or thirty years later, having spent the interval in this country,--bishop, indeed, of the Moravian churches, but a student of fungi all the while,--he reports the same thing from this country; _Proc. Phil. Acad. Sci._, 1834. Cooke also lists it in _Myxomycetes of the U. S._ It surely will be found again. Mr. Lister thinks _P. variable_ Rex may be the same thing.

43. PHYSARUM CARNEUM _G. Lister and Sturgis_.

1910. _Physarum carneum_ G. Lister and Sturgis, _Jour. Bot._,
Vol. XLVIII, p. 63.

Sporangia gregarious, stipitate, sub-globose, .5 mm. in diameter, ochraceous-yellow above, flesh-colored below; peridium membranous, pale yellow, lime-granules evenly distributed; stipe short, translucent, pinkish flesh-colored; capillitium dense, nodules white; spores purplish-brown, spinulose, 8 mu.

Differs from _P. citrinellum_ in the membranous peridium, flesh-colored stalks and smaller spores.

Colorado; _Dr. W. C. Sturgis._

44. PHYSARUM CITRINELLUM _Peck._

1831. _Physarum caespitosum_ Schw., Syn. _N. A. F._, No. 2301 (?).
1869. _Diderma citrinum_ Peck, _Rep. N. Y. Mus._, XXII., p. 89.
1870. _Physarum citrinellum_ Peck, _Rep. N. Y. Mus._, XXXI., p. 55.
1894. _Craterium citrinellum_ List., _Mycetozoa_, p. 74.
1899. _Physarum caespitosum_ Schw., Macbr., _N. A. S._, p. 37.
1911. _Physarum citrinellum_ Peck, List., _Mycetozoa, 2nd ed._, p. 62.

Sporangia gregarious, or scattered globose, short-stipitate, pale yellow or ochraceous, smooth or slightly roughened by the presence of minute lime-particles; peridium more or less distinctly double, the outer calcareous, fragile, the inner very delicate, with here and there a calcareous thickening, ruptured irregularly; stipe very short, half the sporangium, fuliginous, furrowed, expanded below into an imperfectly defined hypothallus; capillitium abundant, the nodes stellate-angular, large, the internodes delicate, short; spore-mass black, spores violaceous-brown by transmitted light, strongly spinulose, 10-12.5 mu.

A very distinct and handsome species. Easily recognizable at sight by its large, globose, almost sessile and yet distinctly stalked sporangia. The color to the naked eye is pale ochraceous or buff. Only under a moderate magnification do the citrine tints come out.

In the _Twenty-second N. Y. Report_, Dr. Peck incorrectly referred this species to _Physarum citrinum_ Schum. On the appearance of Rostafinski's _Monograph_, Dr. Peck in his revised list, _l. c._, writes _P. citrinellum_ Peck, with description on p. 57, following. Under the last name the species has been generally recognized in the United States and distributed. _N. A. F._, 2490.

In the former edition, this species was referred to _P. caespitosum_ Schw., of which the original description is as follows: "_P. caespitosum_ L. v. S., pulcherrimum. In foliis et stipitibus Rhododendri, Bethlehem. Physarum substipitatum aut saltem basi attenuata, caespitosim crescens et sparsim. Caespitulis 3 linearibus; peridiis stipatis, turbinatis, ovatis, basi contracta membranula exterori luteosquamulosa aut punctato-squarrulosa. Sporidiis nigro-brunneis, floccis citrinis inspersis." _Synopsis N. A. Fungi_, 2301.

The type from the Schweinitz herbarium is no longer in evidence. Without it, the reference cannot be sustained.

Not uncommon in the eastern United States; reported also from Japan.

45. PHYSARUM ALBESCENS _Ellis._

PLATE XVI., Figs. 4, 4 _a_.

1889. _Physarum albescens_ Ellis _in litt_: not described.
1893. _Physarum auriscalpium_ Cke., Macbr., _Bull. Lab. N. H. Iowa_,
No. 2, p. 155, in part.
1894. _Physarum virescens_ var. _nitens_ List., _Mycetozoa_, p. 59,
in part.
1899. _Physarum virescens_ var. _nitens_ List., Macbr., _N. A. S._,
p. 34, in part.
1899. _Leocarpus fulvus_ Macbr., _N. A. S._, p. 82.
1911. _Physarum fulvum_ Lister, _Mycet., 2nd ed._, p. 60.
1911. _Physarum virescens, nitens_ List., _Mycet., 2nd ed._, p. 84,
in part.

Sporangia gregarious, scattered, ovoid or globose, pale yellowish or fulvous, opening irregularly above, stipitate; the peridium double, the outer layer more or less calcareous, the inner delicate, almost indistinguishable, persistent below as a shallow cup; the stipe long, weak, striate, fulvous or yellow; hypothallus distinct, venulose, or more or less continuous; capillitium pallid or white, dense, with here and there below large continuous yellow calcareous nodules; columella none; spore-mass black; spores by transmitted light, dark brown, rough, 13-15 mu. Varies to forms with single (inner) peridium and simple physaroid capillitium. _Vid._ descriptions cited for _P. auriscalpium_, _P. nitens_, etc.

This interesting form is from our western mountains, and suggests at first a diderma; but the capillitium is entirely unlike that of a diderma in color and structure, and plainly belongs here. Plasmodium yellow, on fallen leaves and twigs. Our material is from Prof. Bethel, Denver; and Lake Tahoe, Nevada; later from Dr. Weir, Montana. No doubt common at high altitudes near the snow-line in mountainous regions, probably around the world.

As indicated above, this was originally entered as of the genus _Leocarpus_; the taxonomic history of the form may interest readers who note with surprise the presentation in synonymy here developed.

About thirty-five or forty years ago Dr. Harkness of California sent to Mr. Ellis of New Jersey a slime-mould which the sender referred to _Diderma albescens_ Phillips, (_Grev._ V., p. 114, 1877). Ellis sent a small bit to the Iowa herbarium without other comment, save that he thought it a physarum. Sometime later Mr. Ellis received from Father Langlois, a correspondent in Louisiana, specimens he esteemed the same thing. He expressed the opinion that if this were what Phillips had found in California, it should perhaps be called a physarum. The Louisiana material by his courtesy came also to this table. The material was scanty, in poor condition, and all waited further light. To these specimens the writer paid less attention. They were in the hands of his correspondents and the courtesy of the case required their further consideration by Dr. Rex.

In 1889 Mr. Holway found in Iowa, a physarum of which he sent part to Ellis and the remainder to the writer who, then engaged on the _Myxomycetes of East. Iowa_, referred his part of this Iowa gathering to the _Physarum auriscalpium_ Cke. as found in New York. Under this caption a specimen was later sent to Mr. Lister, who has, as we see, consistently regarded the thing as a variety of _P. virescens_ Ditmar, _P. nitens_ List.

Meantime in 1898 Colorado material from Professor Bethel reached the University. This did not recall any of the materials sent from Ellis. _Diderma albescens_ had meanwhile come again from California, and been recognized as _Diderma niveum_ Rost.

Accordingly, in _N. A. S._ the latest arrival from Colorado was described as a new species, and with some temerity perhaps, offered as a second species of the hitherto monotypic _Leocarpus_, all on account of the peculiar capillitium. Sometime after publication our most valued correspondent Mr. Bilgram called attention to the resemblance between the Colorado and Louisiana material already referred to. The University specimens as stated were small, broken, and in every way poor, but enough remained to indicate the evident justice of our correspondent's suspicion. Further investigation of the Holway material in Philadelphia showed that _it too was entitled to consideration_! Inasmuch as the Holway sending was all from one plasmodium, all difficulties vanished at once. The Iowa gathering showed two phases: one at the University represents _P. nitens_, physaroid, single-walled; while the Philadelphia part of the gathering corresponds, poorly it is true, but in fact, as _now_ appears, to the form coming in perfection from Colorado; leocarpine in structure, published as _Leocarpus fulvus_; _P. fulvum_ Lister. Since the combination _P. fulvum_ is already in use, synonym of _P. rubiginosum_, it seems better to write the name suggested by Ellis; _Physarum albescens_ never having been published, because _Diderma albescens_, as noted took care of itself.

Since Rostafinski we separate all these physaroid forms chiefly by capillitial characters: capillitial structure separates genera. _Physarum diderma_ is a physarum despite its double wall. And so here _Leocarpus_ was set out by its differentiating capillitium. In good specimens of the present species a large part of the capillitial net is entirely free from lime, so that when the peridium first opens at the summit, sometimes no trace of lime appears; the calcareous deposits are below, and tend to occupy not the nodal intersections as in _Physarum_, but in large masses involve portions of the net itself, nodes and all, as in _Leocarpus_. Miss Lister's beautiful figures, _op. cit._, Figs. 66 and 82, show this very well.

In The _Journal of Botany_, 52, p. 100, the distinguished author and artist records the discovery of this species in the mountains of Switzerland. She says: "This specimen shows a striking resemblance to _Leocarpus fragilis_ Rost., both in the shape of the sporangia and in the capillitium and spores; but although the color of the sporangia varies in both these species, the walls of _P. (L.) fulvum_ are membranous and rugose with included deposits of lime granules and show nothing of the polished cartilaginous layers characteristic of _L. fragilis_."

The species is a boundary type at best, and shows again how artificial all our taxonomy is apt to prove, when the number of presentations of some particular type becomes larger.

For these reasons, the present author writes _Physarum_, and believes the question of identity in a perplexing case fortunately settled.

46. PHYSARUM VARIABILE Rex.

1893. _Physarum variabile_ Rex, _Proc. Phil. Acad._, p. 371.
1911. _Physarum variabile_ Rex, List., _Mycetozoa, 2nd ed._, p. 47.

Sporangia scattered, stipitate, sub-stipitate or sessile, about 1 mm. high; regularly or irregularly globose, ellipsoidal, obovate or cylindric-clavate in shape; sporangium wall sometimes apparently thick, of a dingy yellow or brownish-ochre color, slightly rugulose on the surface, crustaceous, brittle, rupturing irregularly, sometimes thin, translucent, covered externally with flat circular calcic-masses falling away in patches; stipes nearly equal, occasionally much expanded at the base, rough, longitudinally rugose, variable in size, sometimes one-third of a millimetre high, sometimes a mere plasmodic thickening of the base of the sporangium; color of stipes varying from a yellowish-white to a dull brownish-gray; capillitium a small-meshed network of delicate colorless tubules with large, many-angled, rounded masses of white, or rarely yellowish-white lime-granules at the nodes; no true columella, but often a central irregular mass of white lime-granules; spores dark violet-brown, verruculose, 9-10 mu.

Pennsylvania. _Dr. Rex._

Lister, _op. cit._, describes a variety, _sessile_, presenting plasmodiocarpous fructification, from Ceylon, also from Antigua, but there are some doubts as to the identity of these with American sessile and plasmodiocarpous forms. Vid. _Jour. Bot._ XXXVI., p. 113.

47. PHYSARUM AURISCALPIUM _Cooke_.

1877. _Physarum auriscalpium_ Cooke, _Myx. U. S._, Am. Lyc. Nat. Hist.
N. Y., XI., p. 384.
1877. _Physarum auriscalpium_ Cke., _Myx. Gr. Brit._, Pl. 24,
f. 253-4.
1893. _Physarum sulphureum_ (Alb. & Schw.), Sturgis, _Bot. Gaz._,
XVIII., p. 197.
1898. _Physarum auriscalpium_ Cke., List., _Jour. Bot._, XXXVI.,
p. 115.
1911. _Physarum auriscalpium_ Cke., List., _Mycetozoa, 2nd ed._,
Syn. excl.

Sporangia scattered, stipitate or occasionally sub-sessile spherical, .8-1 mm. high; peridium granulated, bright golden yellow; stipe, when present, one-half to two-thirds the height of the sporangium, blackish-brown; hypothallus, minute, thin, brown; columella absent; capillitium rather dense, composed of large angular nodes, completely filled with bright yellow granules of lime, and connected by very short, delicate, colorless internodes destitute of lime; spores globose minutely verruculose, or asperate, 10.7-11.8 mu in diameter, brownish-violet by transmitted light, black in the mass.

This is the original description, 1893, of _P. sulphureum_ (Alb. & Schw.) Sturgis; the author last named having compared certain stalked New England forms with what he could find of _P. sulphureum_ in the herbarium of Schweinitz at Philadelphia, and having, as he thought, established identity.

Meantime Mr. Lister had been inclined to refer _P. auriscalpium_ Cke. to _P. rubiginosum_ Fr., _Mycetozoa_, p. 61.

In 1898 Professor Sturgis and Mr. Lister agreed that the New England specimens, owing to color and character of stipe and some other differences could not be the Schweinitzian species, but did indeed conform much better with those in London labelled _P. auriscalpium_ Cke.

Accordingly _P. sulphureum_ is something else, very different, (v. A. & S., Cons. _Fung. Tab._, VI., f. 1), and by aid of recent[28] discoveries in Sweden goes its own way again. Meanwhile _P. sulphureum_ Sturgis stands, a new type for _P. auriscalpium_ Cke., the description modified to suit; the lamented pioneer-author receives honor due, and his handsome species, with its "golden graving," may now march, let us hope, under appropriate banner far down the fair highway to future fame!

48. PHYSARUM OBLATUM _Macbr._

PLATE III., Fig. 6; PLATE XIV., Figs. 3, 3 _a_, 3 _b_.

1879. _Physarum ornatum_ Peck, Rep. _N. Y. Museum_, XXXI., p. 40 (?).
1893. _Physarum oblatum_ Macbr., _Bull. Lab. Nat. Hist. Iowa_, II.,
p. 384.
1896. _Craterium maydis_ Morg., _Myx. Miam. Vall._, p. 87.
1909. _Physarum maydis_ Torr., _Flor. des Myxo._, p. 193.
1911. _Physarum maydis_ Torr. List., _Mycet., 2nd ed._, p. 59.

Sporangia gregarious, stipitate, small, bright yellow, globose or depressed-globose, rough; stipe reddish-brown or fuliginous, even, short, slender; hypothallus scant, black, or none; columella none; threads of the capillitium yellow, delicate, connecting the rather dense and abundant yellow lime-granules; spore-mass brownish-black, spores violaceous, minutely but distinctly spinulose, 9-11 mu.

This species is easily recognizable by its brilliant yellow color, somewhat rugose, sometimes scaly peridium, its richly calcareous capillitium, also bright yellow where not weathered or faded, its dark brown, translucent, non-calcareous stem. In dehiscence, the base of the peridium in cup-form, sometimes persists. This circumstance, with the fact that decaying maize-stalks and leaves are a favorite habitat, led Professor Morgan to its description as _Craterium maydis_. But it is doubtless a physarum, occurring on habitats of all sorts, from Ohio to Iowa, Colorado and Washington. Ceylon(?).

_Physarum ornatum_ Peck is doubtfully cited here, although Professor Morgan thought it the same as _P. oblatum_. As a matter of fact the original brief description, _op. cit._, does not suggest either _P. oblatum_ or _P. maydis_; rather a form of _Tilmadoche viridis_. Professor Sturgis, _Notes on Some Type Specimens of Myxo., in the N. Y. Museum, Trans. Conn. Acad. Arts and Sci._, Vol. X., Pt. 2, p. 470, says that of the type almost nothing remains, that the name _P. ornatum_ Pk. "should be discarded."

49. PHYSARUM GALBEUM _Wing._

1890. _Physarum galbeum_ Wing., Ell., _N. A. F._, 2491
(no description).
1892. _Physarum petersii_ Berk. & C., Mass., _Mon._, p. 296, in part.
1894. _Physarum berkeleyi_ Rost., List., _Mycetozoa_, p. 48, in part.
1899. _Physarum galbeum_ Wing., Macbr., _N. A. S._, p. 53.
1911. _Physarum galbeum_ Wing., List., _Mycetozoa, 2nd ed._, p. 59.

Sporangia scattered, globose, stipitate, often nodding, golden yellow, the peridium exceedingly thin, breaking up into patches on which the yellow lime granules are conspicuous; stipe non-calcareous, pale brown or amber-colored, longitudinally wrinkled, about one and one-half times the diameter of the peridium; columella none; hypothallus none; capillitium dense, extremely delicate, the nodes only here and there calcareous, the lime knots when present small, angular, yellow; spore-mass pale brown; spores almost smooth, lilac- or violet-tinted, 7.5-10 mu.

Distinguished among the small delicate species with which it will be naturally associated, by the yellow, richly calcareous wall of the globose sporangium and the almost limeless capillitium. The stipe is hollow and contains irregular masses of refuse granular matter, but no lime so far as we have been able to discover. _P. flavicomum_, to which the species is related most closely, differs in having the wall non-calcareous, iridescent, as well as in the color throughout; the character of the capillitium, in which lime is abundant; the absence of refuse-matter in the stem.

Pennsylvania, Iowa, Minnesota.

50. PHYSARUM TENERUM _Rex._

1890. _Physarum tenerum_ Rex., _Proc. Phil. Acad._, p. 192.
1894. _Physarum polymorphum_ Rost. var. _obrusseum_, Lister,
_Mycet._, p. 48.
1899. _Physarum obrusseum_ (Berk. & C.) Rost., Macbr., _N. A. S._,
p. 52.
1911. _Physarum tenerum_ Rex., List., _Mycetozoa, 2nd ed._, p. 52.

The peridium thin, membranaceous, thickly studded with circular, flattened, yellow granules of lime; stipe long, slender, subulate, opaque, pale brown, striate and black below, pale yellow above; columella none; capillitium yellow or white, delicate, forming a loosely but regularly meshed network with numerous small round or rounded granules at the intersections; spores dark brown, delicately warted, 7-8 mu.

This delicate physarum, very fragile and evanescent, seems to be distinct, by reason of its characteristic rounded lime granules, from any similar, stipitate species. It varies a little according to locality. Ohio specimens are a little larger and have thicker and more calcareous stipes than is usual in those from Philadelphia. The walls of the sporangia when fully matured generally break into several petal-like segments which finally become reflexed. The description given by Berkeley is entirely insufficient.

In an earlier edition this species was entered as _P. obrusseum_ following the Polish text. Miss Lister who has the type of _Didymium obrusseum_ at hand considers it as representing a phase of _Physarum polycephalum_ Schw. _D. tenerrimum_ Berk. & Curt. is judged the same. _P. tenerum_ Rex is, in any event, certain, and the combination is adopted.

Rare:--Pennsylvania, Ohio, Louisiana, Texas, Iowa, Portugal, Japan.

51. PHYSARUM FLAVICOMUM _Berk._

PLATE XV., Figs. 3, 3 _a_.

1845. _Physarum flavicomum_ Berk., _Hook. Jour. Bot._, IV., p. 66.
1873. _Physarum cupripes_, Berk. & Rav., _Grev._, II., p. 65.
1875. _Physarum berkeleyi_ Rost., _Mon._, p. 105.
1894. _Physarum berkeleyi_ Rost., List., _Mycetozoa_, p. 57.
1899. _Physarum flavicomum_ Berk., Macbr., _N. A. S._, p. 53.
1911. _Physarum flavicomum_ Berk., List., _Mycetozoa, 2nd ed._, p. 58.

Sporangia gregarious, small, spherical, at first fuliginous throughout, stipitate; the peridium thin, destitute of lime, iridescent, breaking up and deciduous in patches, except at the base; stipe twice the diameter of the peridium, brown, fluted, not hollow, tapering upward from a small but distinct, radiant hypothallus; columella none; capillitium dense, persistent, the nodes frequently calcareous, elongate and vertical, especially below, yellow; spore-mass brown; spores by transmitted light, bright violaceous-brown, slightly papillose, 9-10 mu.

This species is instantly distinguishable from all cognate forms by its peculiar sooty color. Not less is the species structurally marked by its capillitium. The latter below is exactly as in the species of _Tilmadoche_. Indeed, the present species unites characters supposed to distinguish _Physarum_ from _Tilmadoche_, and would so far justify those authors who bring all the species of both genera together under one generic name. In any case the species is by its capillitium entirely distinct from _P. galbeum_, as well as by the structure of the stipe and the peridial surface. The plasmodium, at first watery, emerges from decayed elm logs and soon takes on a peculiar greenish tint preserved somewhat in the mature fruit.

Rostafinski, _Monograph_, pp. 105, 106, rejects Berkeley's specific name, _flavicomum_, because it refers to the somewhat indefinite, characteristic color. As this is no valid reason for change, we have restored Berkeley's specific name, which by general consent has priority. _N. A. F._, 3299.

Not common. New Jersey, Ohio, South Carolina, Iowa.

52. PHYSARUM BETHELII (_Macbr._) _Lister_.

1899. _Tilmadoche bethelii_, Macbr., _Exempl. ad Herbaria._
1911. _Physarum gyrosum_ Rost., List., _Mycetozoa, 2nd ed._, p. 75.

Sporangia scattered, globose, umbilicate below, .5-1 mm. in diameter, iridescent blue, or sometimes tinged by the presence of delicate pale yellow calcareous scales, stipitate; stipe rather short, black or dark brown, equal; capillitium dense, radiating from the black, slightly intrusive summit of the stipe, and from the base of the peridium ascending; the nodules not numerous, elongate, branching betimes, pale yellow; spores minutely roughened, 10-12 mu.

This beautiful delicately tinted little species is clearly tilmadochoid in the Friesian sense. The capillitium persists after the fall of the upper filmy peridium, adherent below to the persisting peridial base. Collected thus far twice only; by Professor Bethel and by Professor Sturgis, Colorado.