1. Siderocapsa treubii Molisch, 1909. {Siderocapsa Treuhii (sic) Molisch, Ann. Jard. Bot. Buitenzorg, 2 Ser., Supp. 3, 1909, 29; also see Die Eisenbakterien, Jena, 1910, 11.) treu'bi.i. M.L. gen. noun treuhii of Treub; named for Prof. Treub, director of the Tropical Garden at Buitenzorg, Java. Cocci, 0.4 to 0.6 micron in diameter. As many as 8 cells may be embedded in zoo- gloeal masses surrounded by ferric hy- droxide and other iron or manganese com- pounds; these masses are 1.8 to 3.6 microns in diameter. Deposits ferric hydro.xide on the surfaces of water plants. Regarded by Hardman and Henrici (Jour. Bact., 37, 1939, 97) as a heterotrophic organ- ism that utilizes the organic radicle of organic iron compounds, depositing the iron as a waste product on the capsules of the colonies. Source: Found attached to the roots, root hairs and leaves of water plants {Elodea, Nymphaea, Sagittaria, Salvinia, etc.) in Java. Habitat: Widely distributed in fresh water. Epiphytic on submerged plants or on other objects. Abundant in alkaline, hard-water lakes of the drainage type in Minnesota and Wisconsin according to Hardman and Henrici {ibid., 103). Absent in neutral or acid soft-water lakes of the seepage type.
2. Siderocapsa major Molisch, 1909. (Ann. Jard. Bot. Buitenzorg, 2 S^r., Supp. 3, 1909, 29; also see Die Eisenbakterien, Jena, 1910, 13.) ma'jor. L. comp.adj. major larger. Cells colorless, coccus-like, short rods, 0.7 by 1.8 microns. A colony may consist of 100 or more cells in the same mucilaginous capsule. Similar to Siderocapsa treuhii except that the cells are larger and the gelatinous capsule is less sharply defined. May be free- floating in surface films or may be attached to submerged objects. Forms intermediate between Siderocapsa major and Siderocapsa treuhii have been observed by Hardman and Henrici (Jour. Bact., 37, 1939, 97). Source: Found on the surface of a Spiro- gyra sp. near Prague. Habitat: Widely distributed in fresh water.
3. Siderocapsa coronata Redinger, 1931. (Arch. f. Hydrobiol., ££, 1931, 410.) co.ro.na'ta. L. part. adj. coronatus crowned. Coccoid cells, about 1.0 micron in diam- eter, occurring in the primary capsule in groups of 2 to 8. These groups are sur- rounded by secondary gelatinous capsules which may unite into foamy, irregular masses 5 to 10 or more cm in diameter. The capsular material contains deposits of iron and manganese. Free-floating. Yellowish to dark brown in color. Source: Found in water from Upper Lake, Lunz, Austria. Foamy masses are formed in the winter time. Ruttner (Arch, f. Hydrobiol., 33, 1937, 167) reports that the distribution of this organism in Alpine lakes is related to the o.xygen stratification therein : it was found most frequently at depths of from 17.5 to 27.5 meters, where the oxygen range was 0.12 to 0.30 mg per liter. 4.66 mg per liter was the highest oxygen tension at which it was found. Habitat: Presumably widely distributed in water.
4. Siderocapsa eusphaera Skuja, 1948. (Symbolae Bot. Upsal., 9 (3), 1948, 12.) eu.sphae'ra. Gr. prep, eu true; Gr. noun sphaera ball, sphere; M.L. noun eusphaera a true sphere. Cells coccus-shaped, 1 to 2 microns in diameter, 2 to 60 and more in a primary capsule. The latter are 10 to 20 microns in diameter and are surrounded by a large secondary capsule up to 50 microns in diam- eter. The secondary capsules are united into large colonies with a common mucilaginous layer. The secondary capsule stores com- pounds of iron and manganese. Source: Found in lakes in Sweden; found in the plankton at levels where the oxygen tension is low. Habitat: Presumably widely distributed in fresh-water lakes.
