Page:Bergey's manual of determinative bacteriology.djvu/888

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ORDER VIII. MYXOBACTERALES

Polyangiden. Geb. Borntraeger, Leipzig, 1924, 71.) thax'te.ri. M.L. gen. noun thaxieri of Thaxter; named for Dr. Roland Thaxter. Swarm stage (pseudoplasmodium) : Vege- tative stages not observed. Either no germi- nation or prompt cessation of growth on dung extract. May be transferred on dung. Fruiting body: Usually 0.25 to 0.5 mm, occasionally 0.75 mm in diameter. Irregu- larly rounded, superficially sulfur-yellow. Upon pressure numerous reddish convo- luted tubules are observed embedded in a yellow slime. The average diameter of the tubules is about 50 microns. No membrane surrounds the tubes. They contain the shortened rods. Enveloping slime is vari- able. In well developed specimens the slime forms a stalk, giving the whole the appear- ance of a morel. In small specimens the rods are embedded in the slime. The fruiting bodies stand loosely separated on surface of dung, never in large groups. Shortened rods (spores) 0.5 micron by 3 microns, very slender. Habitat: According to Jahn, found only rarely on rabbit dung; races with well de- veloped stalks are even less common. Illustrations: Jahn {ibid., PI. 1, Figs. 1-2) and Krzemieniewski (Acta Soc. Bot. Pol- oniae, 4, 1926, PI. II, Fig. 27). Genus II. Stelangium Ja/»n, 1915. (Kryptogamenfiora der Mark Brandenburg, V, Pilze I, Lief 2, 1915, 205.) Ste.lan'gi.um or Ste.lan.gi'um. Gr. noun stele pillar or column; Or. noun angiutn vessel, container; M.L. neut.n. Stelangixim columnar vessel. Fruiting bodies are columnar or finger-like, sometimes forked, without a definite stalk, standing upright on the substrate. The type species is Stelangium muscorum (Thaxter) Jahn. 1. Stelangium muscorum (Thaxter, 1904) Jahn, 1915. (Chondromyces muscorum Tha.xter, Bot. Gaz., 37, 1904, 411; Jahn, Kryptogamenfiora d. Mark Brandenburg, V, Pilze I, Lief 2, 1915, 205.) mus.co'rum. L. noun muscus moss; L. gen. pi. noun muscorum of mosses. Swarm stage (pseudoplasmodium) : Not described. Fruiting body: Bright yellow-orange, 90 to 300 microns long, 10 to 50 microns wide, without differentiated stalk, simple or rarely furcate, upright, elongate, compact or slender, narrowed at tip. Rods (spores) 1 to 1.3 by 4 to 6 microns. Source: Found on liverworts on living beech trunks in Indiana. Illustrations: Thaxter (op. cit., 1904, PI. 27, Figs. 16-18). FAMILY III. SORANGIACEAE JAHN, 1924. (Beitrage zur bot. Protistologie. I, Die Polyangiden. Geb. Borntraeger, Leipzig, 1924, 73.) So.ran.gi.a'ce.ae. M.L. neut.n. Sorangium type genus of the family; -aceae ending to denote a family; M.L. fem.pl.n. Sorangiaceae the Sorangium family. The shortened rods of the fruiting body lie in angular, usually relatively small cysts of definite polygonal shape. Often many of these cysts are surrounded by a common membrane. The primary cyst may be differentiated from the angular or secondary cysts. No stalked forms are known. Genus I. Sorangium Jahn, 1924. (Beitrage zur bot. Protisitologie. I, Die Polyangiden. Geb. Borntraeger, Leipzig, 1924, 73.)