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 µ. 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.