material is crushed, break off and resemble Nocardia. Odor as on Czapek agar. Potato glucose agar: Growth good to very good. Central area with coarse convolutions or large bumps and irregular ridges sepa- rated by radial grooves which slope to the smooth distinct margin. Surface glossy. Apricot-orange to russet, becoming bay in old cultures. Produces a diffusible pigment which darkens the agar. Sporangia are formed on the margin of some cultures but are absent in most of them. Palisades are formed. Nutrient agar: Growth fair. Center slightly elevated and with a wide flat mar- gin. Color ochraceous orange to cinnamon- rufous. Sporangia very rarely formed. Pali- sade hyphae usually not distinct. Krainsky's glucose asparagine agar: Growth good to very good, consisting of a central area of elevated, fine convolutions, radial ridges or bumps and a smooth area with radial grooves gradually sloping into the submerged margin. Surface moist-ap- pearing and glossy. Color of center apricot- orange to Sayal brown surrounded by an ochraceous salmon or light ochraceous sal- mon margin. Sporangia are usuallj^ on the smooth areas, none being found on the ele- vated parts; they are formed on palisade hj'phae. Distinctive characters: This species is characterized by the predominantly spher- ical sporangia usually on long unbranched stalks, the rather poor and usually flat growth on Czapek agar, and the very dis- tinct palisade hyphae on this medium. The dark brown diffusible pigment on potato glucose agar is also characteristic. Source: Isolated from a small pinch of dry soil (coll. no. P15) collected by Lieu- tenant W. Lane Barksdale in the Philippine Islands, 1945. Genus II. Streptosporangium Couch, 1955. (Jour. Elisha Mitchell Scientific Soc, 71, 1955, 148.) Strep. to. spo.ran'gi.um. Gr. adj. streptus pliant, twisted; Gr. noun spora seed; M.L. noun spora spore; Gr. noun angium a vessel; M.L. neut.n. Streptosporangium pliant sporan- gium. On sterilized leaves of Paspalum grass in water, an inconspicuous mycelium which over- grows the leaves and an aerial mycelium which grows in scattered or concentrically ar- ranged tufts are formed. Aerial mycelium white to pinkish on leaves; the hyphae are much branched, sparingly septate and about 0.5 to 1.2 microns in diameter. Sporangia are formed abundantly on the aerial mycelium on leaves; spores are abundant in the sporangia and are without flagella and non-motile. Growth poor to good on a variety of semi -solid media; aerial mycelium absent to abundant; sporangia and conidia are formed on some nutrient agars. This genus is represented by four isolates representing three distinct species. Two of the species were isolated from soil by the soil dilution method used by Jensen (Proc. Linn. Soc. New So. Wales, 65, 1930-31, 238), and the third one was isolated from dog dung col- lected in New York City by Dr. L. S. Olive. For a comparison of this genus with Actinoplanes , see under the latter. The type species is Streptosporangium roseum Couch. 1. Streptosporangium roseum Couch, 1955. (Jour. Elisha Mitchell Scientific Soc, 71, 1955, 148.) ro'se.um. L. adj. roseus rose-colored. On sterile leaves, either in soil water or on damp sterile soil, a vegetative mycelium is formed which spreads over the surface of the leaf, not penetrating or decolorizing it, and also over the soil; an aerial reproductive mycelium which is white at first but which soon changes to pale pink is also formed. The aerial mycelium appears as single hy- phae or as minute tufts which grow to form mounds, up to 2 mm in diameter, arranged more or less in concentric circles; the mounds usually become minutely pock- marked. Sporangia first appear on scattered single hyphae, apical on the main thread,
