Form‐ Microcoleus

Mi.cro.co' le.us . Gr. adj. mikros small (or thin); Gr. n. koleos sheath; M.L. masc. n. Microcoleus small or thin sheath. Cyanobacteria / Subsection III / Incertae Sedis / Form‐ Microcoleus In members assigned to this form‐genus, two to several trichomes oriented parallel , often spirally and tightly interwoven, are enclosed by a common homogeneous sheath (Figure 1). Cells (diameter 3–6 µm) composing the trichomes are longer than wide (or isodiametric); visible constrictions at the cross‐walls (but usually much less than 1/4 of the cell diameter); mature end cells are conical ; the bundles of filaments generally exhibit slow gliding motility, not involving rotation . Based on analysis of a limited number of isolates, a radial arrangement of thylakoids (in cross‐section, T.E.M.) seems to be typical .