Closterium abruptum var. brevius
(West & G.S.West) West & G.S.West
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Jackl Moor (Austria), Ibmer Moor (Austria), Lauchsee Moor (Austria)
Phylogenetic tree: Closterium abruptum var. brevius
Diagnosis:
- cell crescent-shape, slightly curved, stocky shape
- apices broad, obliquely truncated, terminal pore absent
- inner margin almost straight
- length 100–120 µm, width 16–18
- cell wall with distinct striation
- two chloroplasts, each with 3-4 longitudinal ridges
- several pyrenoids per chloroplast
- girdle bands present
- terminal vacuoles filled with aggregates of crystals
I first found Closterium abruptum var. brevius in June 1995 in the Jackl Moor and the Ibmer Moor and again in July 2024 in the Lauchsee Moor. All these moorland areas are located in Austria.
The shape of Closterium abruptum var. brevius appears compact. The cell is only slightly curved, with the inner margin almost straight. In contrast to the parent form Closterium abruptum, the striation of the cell wall is very distinct. The length of the cells is given by Lenzenweger as 100–120 µm. The specimens I found were considerably longer at around 180–200 µm. However, it cannot be the longer variety Closterium abruptum var. nilssonii, because this species also has only a very delicate striation and the cells are also much slimmer.
Fig. 1 a-d: Closterium abruptum var. brevius. L = 194 µm. Different focal planes of an unsquashed specimen. Obj. 60 X.
Fig. 2 a-b: Closterium abruptum var. brevius. L = 194 µm. The same specimen as shown in fig. 1 a-d in brightfield illumination. Obj. 60 X.
Fig. 3: Closterium abruptum var. brevius. The striation of the cells in a squashed specimen. The ridges vary in width and have varying distances between them. Obj. 60 X.
Fig. 4: Closterium abruptum var. brevius. The truncated apex and the terminal vacuole (TV) which is filled with clusters of crystals. Obj. 60 X.