It will be said, has been said, was said by Fries, that these variations are insignificant, "pendent ex æris constitutione"; but as a matter of fact the several types now in question may be found on the same day, so that evidently something other than the atmospheric environment must determine.
Again it is said that the differences are in external form or color only, the spores in all cases almost if not quite the same. This is true; but specific characters are surface characters in fact: a species morphologically is merely the form in which a kind or genus presents itself. If the presentation be constant, for our convenience we say so, in bestowing a name. Whether in our present treatment the convenience is purely personal, students may decide.
However it all may be, there are in this part of the world many varying presentations of Fuligo capable of illustration and description; the same forms, perhaps, which have attracted the notice of the more acute mycologists in the older history of the subject. Some of these forms we here venture to describe, with such annotation as may show something of present knowledge.
Key to the Species of Fuligo
| A. Æthalium 1 cm. or less; spores spherical | 1. F. muscorum | |
| B. Æthalium larger, or plasmodiocarpous, even sporangi-form, crust white, smooth, even, spores elliptical | 2. F. cinerea | |
| C. Æthalia larger, 2 cm. or more. | ||
| 1. Cortex yellow, etc., not white; spores 6–8 µ | 3. F. septica | |
| 2. Cortex nearly or quite wanting; spores 10–12 | 4. F. intermedia | |
| 3. Cortex white, a foamy crust; spores 15–25 | 5. F. megaspora | |
1. Fuligo muscorum Alb. & Schw.
- 1894. Fuligo muscorum, Alb. & Schw. Lister, Mycetozoa, p. 67.
- 1875. Licea ochracea Peck, N. Y. Rep., XVIII., p. 55.
- 1879. Fuligo ochracea Peck, N. Y. Rep., XXXI., p. 56.
- 1894. Fuligo muscorum, Alb. & Schw., Lister, Mycetozoa, p. 67.
- 1911. Fuligo muscorum Alb. & Schw., Lister, Mycetozoa, 2nd ed., p. 87.
Plasmodium orange-yellow. Æthalium globoid, very small, 1 cm. or less, the cortex very thin, greenish yellow; sporangial walls not evident; capillitium well-developed, the numerous calcareous nodes fusiform or often branching, and connected by rather short, transparent internodes; spores coarsely warted, 10–11 µ.
This form seems to differ from F. septica chiefly in its constant diminutive habit of fruiting, in its delicate cortex, and in its spores, brighter, larger, and more coarsely warted. The descriptions and figure by Schweinitz seem referable to nothing else. First reported by Albertini and Schweinitz from Germany; by Schweinitz from the Carolinas; then by Dr. Peck described as a Licea from New York. It seems less commonly collected in the United States.