Tribonema affine
(Kützing) West, 1904
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Simmelried
Phylogenetic tree: Tribonema affine
Diagnosis:
- filaments long, hardly contricted at septa
- cells elongated cylindrical, width 4–6 µm, up to 14–20 time longer than broad
- 1–3 chloroplasts per cell, trough- or ribbon-shaped, lobed, slightly spirally
- no pyrenoids
- cell wall smooth
I often find Tribonema affine between floating plant masses from the Simmelried. Tribonema affine can be recognize by the slender, smooth cells and the fact that the septa are not or only very slightly constricted. The cells contain 1–3 yellow-green chloroplasts without pyrenoids, which are often somewhat spiral and lobed. This distinguishes Tribonema affine from the similar species Tribonema minus, whose chloroplasts are not lobed and whose cells are much more compact and barrel-shaped. The other described species of the genus Tribonema either have a different number or shape of chloroplasts, or the cell filaments are thicker or thinner.
Fig. 1 a-c: Tribonema affine. L = 15–24 µm (of cells). Three focal planes of a part of a 4.7 µm broad filament. Note the 1-2, lobed and spirally chloroplasts (Chl 1, Chl 2) per cell. Bteween the chloroplast the nucleus (Nu) is located. Obj. 100 X.
Fig. 2 a-b: Tribonema affine. L = 24–39 µm (of cells). Two focal planes of a second, 4.1 µm broad filament. Nu = nucleus. Obj. 100 X.