Key to the species of genus Mycoplana.
I. Gelatin not liquefied
1. Mycoplana dimorpha.
II. Gelatin liquefied.
2. Mycoplana bullata.
1. Mycoplana dimorpha Gray and Thornton, 1928. (Cent. f. Bakt., II. Abt., 73, 1928,82.) di.mor'pha. Gr. adj. diniurphus two forms. Short, curved and irregular rods, 0.5 to 0.7 by 1.25 to 4.5 microns, showing branch- ing especially in young cultures. Originally reported as "polar, peritrichous". Draw- ings show some cells with a polar flagellum and others where the several flagella shown could represent a tuft of polar flagella. Cultures preserved in the American Type Culture Collection have been retested (T. H. Lord, Manhattan, Kansas; F. E. Clark, Beltsville, Maryland) and show typical pseudomonad cells, i.e., straight rods with a single polar flagellum. Meanwhile P. H. H. Gray (Macdonald College, Quebec) reports that his cultures still show branching cells on the media he uses. Gram-negative. Gelatin colonies: Circular, bufi", smooth, resinous, entire. Gelatin stab: No liquefaction. Growth filiform. Agar colonies: Circular, buff, convex, smooth, glistening, entire. Agar slant: Filiform, white, convex, glistening, entire. Broth: Turbid, with surface ring. Nitrites not produced from nitrates, but gas evolved in fermentation tubes. Starch hydrolyzed. No acid from carbohydrate media. Attacks phenol. Aerobic. Optimum temperature, below 30° C. Source : Only one strain was found in soil by Gray and Thornton {loc. cit.). Wood (Aust. Jour. Marine and Freshwater Res., 4, 1953, 184) identifies 1010 cultures out of 2969 cultures isolated from Australian marine habitats as belonging to this species. Some appeared on svibmerged glass slides as attached forms. A diversity of characters was found in these cultures, indicating that many of them should not have been identi- fied as belonging to this species or even to this genus. For example, while it is stated in one place that carbohydrate fermentation is feeble, it is stated in another place that about 50 per cent of the cultures actively fermented maltose and sucrose, these sugars being fermented more actively than glucose. Some cultures are reported as attacking cellulose, others as attacking alginates or even chitin. In other words many of the cul- tures identified as Mycoplana dimorpha possessed characters not ascribed to the species by Gray and Thornton. Apparently all cultures from marine habitats that were Gram-negative branching forms were identi- fied as Mycoplana dimorpha unless they showed a yellow, pink or lemon-yellow chro- mogenesis. Wood's work would indicate that branching, polar flagellate species of very diverse physiologies exist in marine habitats that are as yet scarcely studied from the standpoint of the species present. M. E. Norris of the Pacific Fisheries Experiment Station, Vancouver, B.C. reports (personal communication. May, 1954) that she also finds Gram-negative, branching, polar flagellate organisms in sea water. Habitat: Probably widely distributed in soil. Possibl}^ also found in marine habitats.
2. Mycoplana bullata Gray and Thorn- ton, 1928. (Cent. f. Bakt., II Abt., 73, 1928, 83.) bul.la'ta. L. adj. bullatvs with a knob. Rods curved or irregular in shape, branch- ing, 0.8 to 1.0 by 2.25 to 4.5 microns. Origi- nally stated to be either "polar or peri- trichous" in its flagellation, but recent studies show that the American Type Cul- ture Collection culture of this organism is polar flagellate. It resembles Mycoplana liiinurpha in this respect. Gram-negative. Gelatin colonies: Circular, buff, smooth, glistening; edge diffuse. Gelatin partially liquefied.
