Poitrasia
POITRASIA Kirk, 1984 (Mycol. Papers 152:51); 1 sp. ( Kirk, 1984—monograph).
Sporangiophores simple, arising directly from the substrate or the aerial hyphae. Sporangia more or less globose, columellate, wall brown and persistent, splitting into two or three sections along preformed sutures, multispored. Sporangiospores ellipsoid, longitudinally striate, bearing hyaline appendages at each pole. Zygospores with a smooth zygosporangial wall and a striate zygospore wall, brown, borne between tongs-like suspensors (Kirk, 1984). Few-spored sporangia not produced.
Type species: P. circinans
Species of Poitrasia:
P. circinans (Naganishi & Kawakami) P.M. Kirk, 1984 (Mycologial Papers 152:52).
Poitrasia circinans was described (as Blakeslea circinans) by Naganishi and Kawakami (1955), and it was included in the review of the Choanephoraceae by Hesseltine and Benjamin (1957). Mikawa (1979) included the taxon in his series on the Mucorales of Japan. Kirk (1977) studied the ontogeny of the zygospores of Choanephora circinans and he (Kirk, 1984) transferred the species to a new monotypic genus, Poitrasia circinans.
Poitrasia circinans can be isolated from soil in Florida during the summer and probably other regions where Blakeslea trispora and Choanephora cucurbitarum also are encountered. Poitrasia is not commonly reported but may be overlooked because the sporangia only are formed on a few, nutrient-poor media not commonly used in soil studies. On most media Poitrasia looks like Choanephora cucurbitarum or Blakeslea trispora colonies that do not form sporulating structures.
Bibliography
Hesseltine, C.W., and C.R. Benjamin. 1957. Notes on the Choanephoraceae. Mycologia 49:723-733.
Kirk, P.M. 1977. Scanning electron microscopy of zygospore formation in Choanephora circinans (Mucorales). Trans. Brit. Mycol. Soc. 68:429-434.
Kirk, P.M. 1984. A monograph of the Choanephoraceae. Mycol. Paper 152:1-61.
Mikawa, T. 1979. A taxonomic study on Japanese sporangiferous Mucorales (6). J. Japan. Bot. 54:289-300..
Naganishi, H., and H. Kawakami. 1955. On Blakeslea Thaxter in Japan. (II) Bl. circinans sp. nov. Bull. Fac. Engineer., Hiroshima Univ. 4:183-187.
Updated Mar 13, 2005
