Genus III. Thiocapsa Winogradsky, 1888.
(Schwefelbacterien, Leipzig, 1888, 84.)
Thi.o.ca′psa. Gr. n. thium sulfur; L. n. capsa a box; M.L. fem. n. Thiocapsa sulfur box.
Cells spherical, occurring in families of irregularly arranged individuals held together in a common slime capsule. The aggregates are spread out flat on the substrate. Motility not observed. As the colony grows, the capsule bursts, and the cells are spread apart. General morphology and development thus appear similar to that in the genus Aphanocapsa among the blue-green algae. Contain bacteriochlorophyll and carotenoid pigments; capable of photosynthesis in the presence of hydrogen sulfide. Under such conditions sulfur is stored in the form of globules in the cells. This genus is so much like Thiothece that it is doubtful whether a distinction can be maintained.
The type species is Thiocapsa roseopersicina Winogradsky.
Key to the species of genus Thiocapsa.
I. Individual cells about 3 microns in diameter.
1. Thiocapsa roseopersicina.
II. Individual cells about 1.5 microns in diameter.
2. Thiocapsa floridana.
1. Thiocapsa roseopersicina Winogradsky, 1888. (Schwefelbacterien, Leipzig, 1888, 84).
ro.se.o.per.si.ci′na. L. adj. roseus rosy; Gr. noun persicus the peach, Persian apple, Persian; M.L. adj. roseopersicinus rosy-peach (colored).
Cells spherical, 2.5 to 3 microns in diameter, occurring in families of irregularly arranged individuals held together in a common slime capsule. Motility not observed. Usually a distinct rose-red. Stored sulfur droplets may attain a considerable size.
Habitat: Mud and stagnant bodies of water containing hydrogen sulfide and exposed to light; sulfur springs.
Illustration: Winogradsky, loc. cit., Plate IV, fig. 15.
2. Thiocapsa floridana Uphof, 1927. (Arch. f. Hydrobiol., 18, 1927, 84.)
flo.ri.da′na. M.L. adj. floridanus pertainng to Florida.
Cells spherical, about 1.5 microns in diameter. In groups of irregular colonies, each surrounded by a common capsule, several colonies being stuck together. Motility not observed.
Source: Palm Springs, Florida and Lake Sakskoje, near Eupatoria, Crimea.
Habitat: Mud and stagnant water containing hydrogen sulfide and exposed to light; sulfur springs. Probably ubiquitous.
Illustration: Uphof, ibid., 83, fig. VI.
Genus IV. Thiodictyon Winogradsky, 1888.
(Winogradsky, Schwefelbacterien, Leipzig, 1888, 80; Rhododictyon Orla-Jensen, Cent. f. Bakt., II Abt., 22, 1909, 334.)
Thi.o.dic′ty.on. Gr. noun thium sulfur; Gr. noun dictyum or dictyon net; M.L. neut. n. Thiodictyon sulfur net.
Cells rod-shaped, frequently with pointed ends, somewhat resembling spindles. Form aggregates in which the cells become arranged end to end in a net-like structure, somewhat reminiscent of the shape of the green alga Hydrodictyon. The shape is not constant; cells may also form more compact masses. Sometimes groups of cells separate from the main aggregate by active movements. Common gelatinous capsule not observed. Contain bacteriochlorophyll and carotenoid pigments; cells usually very faintly colored. Capable of photosynthesis in the presence of hydrogen sulfide, the cells then storing sulfur as small globules.
