- 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.
The Journal of the Cin. Soc. Natural History
Vol. XIX. Plate XIV.
Morgan on Myxomycetes.
B. Sporangia sessile.
22. Physarum plumbeum Fr. Sporangia small, globose or obovoid, sessile, on a narrow base, gregarious, sometimes close but seldom confluent; the wall a thin violaceous membrane, with a very thin layer of small white scales and minute granules of lime, sometimes naked. Capillitium a loose net-work of slender tubules, with slight expansions at the angles; the nodules of lime white, numerous, more or less elongated, irregularly lobed and branched. Spores globose, even, violaceous, 7–9 mic. in diameter.
Growing on old leaves, sticks, etc. Sporangia .3-.4 mm. in diameter, quite regular in shape, attached by a narrow base, sometimes by a mere point, rarely confluent. The lime on the wall of the sporangium is rather scanty, sometimes altogether absent, and the nodules of lime in the capillitium are rather small. The species is figured by Micheli N. P. G. Tab. 96, Fig. 9. It is named by Fries S. M., III, p. 142. It is figured again by De Bary, Die Mycetozoen, Tafel I.
23. Physarum atrum Schw. Sporangia sessile, subglobose or oblong, by confluence, more or less elongated, bent or flexuous and branched; the wall a thin violaceous membrane, rugulose, covered by a wrinkled and reticulate layer of white granules of lime, which sometimes become thin or disappear. Capillitium a loose net-work of tubules, more or less expanded at the angles; the nodules of lime white, numerous, large, irregularly lobed and branched. Spores globose, very minutely warted, violaceous, 8–10 mic. in diameter.
Growing on old leaves, bark, grasses, etc.; apparently the most common of these three cinereous species. Sporangia .3-.5 mm. in thickness, some of them roundish or oblong, others elongated to several millimeters. The sporangium is often elegantly reticulate as observed by Schweinitz even when the lime is quite scanty. In Saccardo's Sylloge Berlese changed the name to Physarum reticulatum, but this is unnecessary, as the Physarum atrum of Fries is not a Myxomyces.
24. Physarum cinereum Batsch. Sporangia large, subglobose, sessile, gregarious, sometimes close and confluent; the wall a thin violaceous membrane, with a closely adherent layer of minute granules, over which are scattered irregular white scales of lime. Capillitium of tubules forming a loose net-work, with wide expansions at the angles; the nodules of lime numerous, white, very large, with pointed angles and lobes, by confluence often branched and reticulate, and occasionally forming a pseudo-columella in the center of the sporangium. Spores globose, minutely warted, dark violaceous, 10–13 mic. in diameter.
Growing on old wood, leaves, etc. The sporangia .4-.6 mm. in diameter, more or less irregular. The great abundance of lime in the capillitium and the large distinctly warted spores distinguish this species. Physarum cinereum of Persoon's Synopsis, Didymium cinereum of Fries' Systema. The only American specimens I have of this species are from Iowa (McBride) and from Nebraska (Webber).