Part 23

Growing on old wood, sticks, leaves, etc. Sporangia .4-.6 mm. in diameter, by confluence sometimes much elongated; the lime-nodules two or three times the diameter of the spores in thickness. Didymium lateritium B. & R. Physarum inequale Peck, is the same species.

§2. SAXELLA. Lime in the capillitium abundant, the nodules large, angular or irregular, with pointed lobes and branchlets.

A. Sporangia stipitate.

15. PHYSARUM IMITANS, Racib. Sporangium depressed-globose, the base flattened or umbilicate, stipitate, erect or cernuous; the wall a thin violaceous membrane, with a closely adherent layer of minute granules, over which are scattered rather large, roundish or irregular white scales of lime, splitting from the apex downward into a few irregular segments. Stipe short, thick at the base and tapering upward, longitudinally rugulose, from gray to brown or blackish, especially below. Capillitium a loose irregular network of tubules, widely expanded at the angles; the nodules of lime white, numerous, large, irregular, with pointed angles and lobes. Spores globose, very minutely warted, violaceous, 8-9 mic. in diameter.

Growing on old wood, mosses, etc. Sporangium .4-.5 mm. in diameter, the stipe about the same length or a little longer. The species superficially resembles the gray form of Physarum nutans, and quite likely is constantly overlooked on this account. Although I am not able to verify my reference, yet my specimens answer so well to the description of Raciborski that I am unwilling to invent a new name.

16. PHYSARUM ORNATUM, Peck. Sporangium globose or depressed-globose, stipitate; the wall a thin yellowish membrane, covered with minute granules and small irregular scales of lime, yellow to orange in color. Stipe short, erect, blackish-brown, black at the base, longitudinally plicate, rising from a small hypothallus. Capillitium of tubules forming a rather dense net-work, with wide expansions at the angles; the nodules of lime large, numerous, yellow, irregular, sometimes confluently branched and reticulate. Spores globose, minutely warted, dark violaceous, 10-12 mic. in diameter.

Growing on old wood, bark, mosses, etc. Sporangium about .5 mm. in diameter, the stipe about the same length or shorter. Physarum oblatum McBride, can not be distinguished from this. Specimens of this species in the herbarium of Schweinitz are labeled Physarum sulphureum; this is without doubt a mistake.

17. PHYSARUM GRAVIDUM, Morgan, n. sp. Sporangium depressed-globose, the base umbilicate, stipitate; the wall a thin, violaceous membrane, brownish at the base, with a thin coat of small, white scales and minute granules of lime. Stipe long, erect, brown or reddish-brown, darker below, tapering upward, expanding at the base into a small hypothallus. Capillitium of slender tubules forming a loose net-work, more or less expanded at the angles and for the most part filled with lime; the nodules white, slender, much elongated and branched, with pointed lobes and branchlets. Spores globose, very minutely warted, dark violaceous, 11-13 mic. in diameter.

Growing on old stalks of Zea mays. Sporangium .5-.6 mm. in diameter, the stipe about twice this length. The lower part of the capillitium is sometimes entirely filled with lime, so that the species approaches Badhamia in the structure of its capillitium.

18. PHYSARUM LEUCOPUS, Link. Sporangium globose, the base slightly flattened, stipitate; the wall a thin, violaceous membrane, with a white, pulverulent outer coat of minute granules of lime. Stipe short, thick, erect, snow-white, longitudinally rugulose, tapering upward, expanding at the base into small, white hypothallus. Capillitium a loose net-work of tubules, with wide expansions at the angles; the nodules of lime large, white, numerous, irregularly lobed and branched. Spores globose, very minutely warted, violaceous, 8-10 mic. in diameter.

Growing on old wood, leaves, etc. Sporangium .3-.4 mm. in diameter, the stipe about the same length as the diameter. Our specimens are a smaller form than the European, with smaller and smoother spores. Superficially the species resembles Didymium squamulosum, and it is Didymium leucopus of Fries, S. M.

19. PHYSARUM GLAUCUM, Phillips. Sporangium globose, or the base slightly depressed, stipitate; the wall a thin, violaceous membrane, covered with minute, white granules and small roundish or irregular scales of lime. Stipe short, stout, erect, black, longitudinally wrinkled, expanding at the base into a small hypothallus. Capillitium of much-flattened tubules, forming a loose net-work, widely expanded at the angles; the nodules of lime numerous, large, white, irregular, with pointed angles and lobes. Spores globose, very minutely warted, dark violaceous, 12-14 mic. in diameter.

Growing on old leaves: California. Sporangium .5-.7 mm. in diameter, the stipe not longer than the diameter. This is quite a robust species, both externally and in the broad, flat tubules of the capillitium.

20. PHYSARUM RELATUM, Morgan, n. sp. Sporangium globose, the base umbilicate, stipitate, often cernuous; the wall a thin, violaceous membrane, rugulose and iridescent, covered with small, roundish or irregular white scales of lime. Stipe long, erect or inclined, rising from a thin hypothallus, tapering upward, white or cream color to ochraceous. Capillitium a dense net-work of tubules, more or less expanded at the angles, and almost entirely filled with white granules of lime, leaving only here and there short, slender empty spaces. Spores globose, nearly smooth, violaceous, 8-9 mic. in diameter.

Growing on old wood. Sporangium .5-.6 mm. in diameter, the stipe about twice this length. The capillitium is rigid, with the abundance of lime almost as in the genus Badhamia. Superficially the species much resembles Cytidium globuliferum or Physarum compactum, but the disposition of the lime on the wall and in the capillitium is altogether different.

21. PHYSARUM AURISCALPIUM, Cke. Sporangia subglobose, depressed, substipitate; the wall a hyaline membrane with a thin, closely adherent layer of minute granules of lime, over which are scattered large, irregular, orange-red scales of lime. Stipe very short, sometimes almost obsolete. Capillitium of tubules forming a loose net-work, with widely expanded angles, and mostly filled with orange granules of lime, only here and there short, slender, empty spaces. Spores globose, minutely warted, dark violaceous, 11-13 mic. in diameter.

Growing on rotten wood; South Carolina, Ravenel. Sporangia .6-.8 mm. in diameter, the stipe very short. Described in Annals of the Lyceum of Natural History of New York, June, 1877. So fine a species ought to be found again. Cooke's specimen was examined by Lister, Mycetozoa, p. 61.

EXPLANATION OF PLATE XIV.

Fig. 56.--Craterium minimum, B. & C. a. Sporangia × 5. b. Sporangium with lid × 90. c. Capillitium and spores × 500.

Fig. 57.--Craterium maydis, Morgan. a. Sporangia × 5. b. Sporangium × 90. c. Capillitium and spores × 500.

Fig. 58.--Physarum obrusseum, B. & C. a. Sporangia × 5. b. Sporangium × 90. c. Capillitium and spores × 500.

Fig. 59.--Physarum connexum, Link. a. Sporangia × 5. b. Sporangium × 90. c. Capillitium and spores × 500.

Fig. 60.--Physarum polycephalum, Schw. a. Sporangia × 5. b. Sporangia × 90. c. Capillitium and spores × 500.

Fig. 61.--Physarum lateritium, B. & C. a. Sporangia × 5. b. Sporangia × 90. c. Capillitium and spores × 500.

Fig. 62.--Physarum imitans, Racib. a. Sporangia × 5. b. Sporangium × 90. c. Capillitium and spores × 500.

Fig. 63.--Physarum relatum, Morgan. a. Sporangia × 5. b. Sporangia × 90. One divested of the wall and showing the rigid capillitium. c. Capillitium and spores × 500.

VOL. XIX. PLATE XIV.

MORGAN ON MYXOMYCETES.]