Linn. Soc. New So. Wales, 56, 1931, 257; Waksman and Henrici, in Manual, 6th ed., 1948, 953.) hy.gro.scop'i.cus. Gr. adj. fiyynis moist; Gr. noun scopiis watcher; M.L. adj. hygro- scopicus detecting moisture or covered with moisture. Vegetative growth: Hyphae 0.6 to 0.8 mi- cron in diameter. Aerial mycelium: Hyphae long, tangled, branched, 0.8 to 1.0 micron in diameter. Spirals numerous, sinistrorse, narrow, usu- allj^ short, only 1 or 2 turns, closed, typically situated as dense clusters on the main stems of the aerial hyphae. Spores ellipsoidal, 0.8 to 1.0 by 1.0 to 1.2 microns. Gelatin: Slow liquefaction. No pigment produced. Agar: Good growth; raised, wrinkled, glossy, cream-colored; later yellowish gray with yellowish brown reverse. Occasionally a scant white aerial mj^celium. Sucrose agar: Good to abundant growth. Vegetative mycelium heavy, superficially spreading, folded, glossy surface, white to cream-colored, later sulfur-yellow to yellow- ish gray, with golden to light orange reverse. Soluble pigment of the same color. Aerial mycelium scant, thin, white or absent. Glucose agar: Good growth; granulated, cream-colored to straw-yellow, later dull chrome-yellow to brownish orange. Aerial mycelium thin, smooth, dusty, white to pale yellowish gray, after 1 or 2 weeks more or less abundantly interspersed with small, moist, dark violet-gray to brownish patches which gradually spread over the whole sur- face. Light yellow soluble pigment. Potato: Fair growth. Vegetative my- celium raised, wrinkled, cream-colored, later yellowish gray to dull brownish. Aerial mycelium absent or trace of white. Milk: Completely digested in 3 to 4 weeks at 30° C. without any previous coagulation. The reaction becomes faintly acid (pH 6.0 or less). Sucrose is inverted. Starch is hydrolj^zed. Cellulose is decomposed readily by some strains. Nitrates not reduced with sucrose as source of energy. Antagonistic properties: Positive. Distinctive character: In this species, the aerial mycelium (which in other actinomy- cetes is strikingly hydrophobic) on certain media (glucose or glycerol asparagine agar) becomes moistened and exhibits dark, glis- tening patches. These patches, when touched with a needle, prove to be a moist, smeary mass of spores. This characteristic feature is not equally distinct in all strains. Source: Seven strains were isolated from soils. Habitat: Soil. 100. Streptomyces longisporoflavus (Krassilnikov, 1941) Waksman, 1953. (Ac- tinomyces longisporus flavus Krassilnikov, Guide to the Actinomycetes, Izd. Akad. Nauk, U.S.S.R., Moskau, 1941, 30; Waks- man, in Waksman and Lechevalier, Actino- mycetes and Their Antibiotics, Baltimore, 1953, 94.) lon.gi.spo.ro.fla'vus. L. adj. longus long; Gr. noun spora a seed; M.L. fem.n. spora a spore; L. adj. flavus 3'ellow; M.L. adj. longisporoflavus long-spored, yellow. Vegetative growth: Yellow, lemon-yellow or dirty yellow, seldom golden yellow colonies. Pigment not soluble. Some strains have a greenish tinge, depending on the composition of the medium. Aerial mycelium: Well developed, velvety, whitish yellow to brownish yellow. Sporo- phores produce long, open spirals. Spores cylindrical or elongated, 1.0 to 1.5 by 0.7 microns; some with rounded ends and swol- len in center. Gelatin: Liquefaction in 10 to 15 days. Milk: Coagulated; slowly peptonized. Sucrose not inverted. Starch is weakly hj'drolyzed. No growth on cellulose. Nitrites actively produced from nitrates. Antagonistic properties: Weakly antago- nistic. Source: Isolated from soil. Habitat: Soil. 101. Streptomyces candidus (Krassil- nikov, 1941) Waksman, 1953. (Actinomyces candidus Krassilnikov, Guide to the Actino- mycetes, Izd. Akad. Nauk, U.S.S.R., Mos- kau, 1941, 49; Waksman, in Waksman and Lechevalier, Actinomycetes and Their
