Nostoc
Gelatinous Balls
Nostoc, Gelatinous Balls. Nostoc is a large genus of cyanobacteria, which occur on land as well as water. The type illustrated here exisits as spherical structures attached to stones in flowing water. The 'balls' consist of a holdfast, a rubbery outer coat enclosing a mass of jelly, and threads of phtosynthetic cells. The balls are clearly visible, being 8-10mm in diameter.
Photograph detail
Slide 1: Nostoc, Ball, showing holdfast which is on lower surface. Holdfast attaches to stone. Collected from Galeclose Beck, Hargill, Redmire. May.
Slide 2: Nostoc, attached to stones. Galeclose Beck, Hargill, Redmire. May.
Slide 3: Nostoc, attached to stones. Galeclose Beck, Hargill, Redmire. May.
Slide 4: Nostoc. Threads of photosynthetic cells from the ball. Photographed at x400, brightfield illumination. Collected from Galeclose Beck, Hargill, Redmire. May.
Slide 5: Nostoc. Threads of photosynthetic cells from the ball. Photographed at x1000, oil immersion, brightfield illumination. Collected from Galeclose Beck, Hargill, Redmire. May.
Slide 6: Nostoc. Threads of photosynthetic cells from the ball. Photographed at x1000, oil immersion, brightfield illumination. Collected from Galeclose Beck, Hargill, Redmire. May.