- 1829. Sub-order Myxogastres Fries, Syst. Myc., III., p. 67.
- 1833. Sub-order Myxomycetes Link, Handb. der Gew., 3, p. 405.
- 1833. Sub-order Myxomycetes Wallroth, Fl. Crypt., II., p. 333, in part.
- 1858. Class Mycetozoa DeBary, Bot. Zeitung, 1858, pp. 357–365, in part.
- 1889. Class Myxogastres Schroeter, Engl. u. Prantl, Nat. Pflanz., I., i., p. 16.
- 1892. Class Myxogastres (Fries) Massee, Monograph, p. 28.
- 1894. Class Mycetozoa Lister, Mycetozoa, p. 21, in part.
Except as just described, the slime-moulds present abundant, minute, unicellular spores, enclosed in sporangia more or less perfectly defined, and attended by peculiar thread-like structures, free or variously attached and conjoined, the so-called capillitium.
So far as known, the spores on germination give rise to zoöspores, at first amœboid, later ciliate, again amœboid, conjugating in pairs, then, in some cases, at least, coalescing and dividing indefinitely to form the plasmodial or vegetative phase.[17]
Key to the Orders of the Myxogastres
| Spore-mass black or violaceous, rarely ferruginous | Series A |
| Spore-mass never black; usually some shade of brown or yellow, rarely purplish or rosy, etc. | Series B |
Series A
| 1. Capillitium present, delicate, thread-like; sporangia calcareous more or less throughout | I. Physarales |
| 2. Capillitium present, thread-like, arising usually as anastomosing branches from a well-developed columella, which in a single genus contains lime; sporangia otherwise non-calcareous | II. Stemonitales |
Series B
| 3. Capillitium none, or very imperfectly developed; spores of some shade of brown, rarely purplish | III. Cribrariales |
| 4. Capillitium the inwardly produced irregular extremities of plates or tubules, which by their interweaving outwardly make up the aethalial wall; spores pale, ashen | IV. Lycogalales |
| 5. Capillitium made up of more or less distinctly sculptured threads, parietal or free, simple, branched, or reticulate; spores commonly yellow | V. Trichiales |