Pseudocarteria, a volvocid flagellate distinguished from the similar genus Carteria by absence of an anterior papilla. Four approximately equal-length flagella and single large chloroplast. Prominent stigma. From freshwater pond near Boise, Idaho. Oblique illumination. This image was taken by William Bourland. He now uses a Zeiss Axioskop 2 with Spot Insight and Spot Flex CCD cameras (Diagnostic Instruments). Image copyright: William Bourland, image used under license to MBL (micro*scope).
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Freshwater and Terrestrial Microbes of Idaho (USA) and Elsewhere
|Description of Pseudocarteria: Cells mostly radially symmetrical; cell shape spherical, ovoid, ellipsoidal or cylindrical; cell wall adheres to the protoplast, gelatinous sheath sometimes present; 4 equal flagella; chloroplast axial, shape diffuse or distinctly asteroid; pyrenoid central; nucleus located anteriorly or centrally and then completely surrounded by the pyrenoid; eyespot present, located in a median position; contractile vacuoles several, irregularly distributed; asexual reproduction by 2 or 4 zoospores; sexual reproduction (one species) homothallic and anisogamous, 8-16 male gametes formed in one gametangium, a single, larger female gamete formed without preceding cell divisions; male gametes with fertilization tubule; zygote initially with 8 flagella, when mature with spiny, thick cell wall. |