Nostoc sphaericum Vaucher ex Bornet & Flahault (1886: 208)

Mcgregor, Glenn B., 2018, Freshwater Cyanobacteria of North-Eastern Australia: 3. Nostocales, Phytotaxa 359 (1), pp. 448-450 : 448-450

Nostoc sphaericum Vaucher ex Bornet & Flahault (1886: 208) Fig. 50 C–D .

Colonies ± spherical, with a firm, smooth periderm, olive-green to yellow-brown in colour, up to 3.5 cm in diameter, free-living or amongst other algae and aquatic vegetation. Individual sheaths usually only visible in mature colonies, where filaments may be surrounded by a distinct, often yellowed and slightly lamellated sheath. Vegetative cells ± barrel-shaped, isodiametric or slightly longer than broad, 3.5–5.5 μm long × 4.1–4.8 μm wide. Heterocytes spherical to oval, 5.5–7.9 μm long × 4–6 μm wide. Akinetes oval, 4.4–6.5 μm long × 4.4–6.6 μm wide, up to 5 in series.

Specimens examined:—Eurong Beach stream #1, Great Sandy Natl Park, Fraser Is. Section.

Observations:—Growing amongst filamentous algae in a shallow, coastal stream draining dune wetlands.

Other records:— Queensland: May (1978), McLeod (1975), Sonder (1880, 1881).

Figures

FIGURE 50. A–B Nostoc sp. B; C–D Nostoc sphaericum. Scale bars = 20 μm