828 



ORDER V. ACTINOMYCETALES 



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, 



