Pediastrum duplex var. asperum

(A. Braun) Hansgirg, 1855

Most likely ID: n.a.

 

Synonyms: Pediastrum pertusum var. asperum, Pediastrum angulosum var. asperum 

 

 

Sampling location: Pond of the convent Hegne

 

Phylogenetic tree: Pediastrum duplex var. asperum

 

Diagnosis: 

  • coenobium star-shaped, flat and single layered
  • diameter coenobium about 80 µm
  • coenobium of (4)–8–16–32–(64) cells
  • cell wall with a reticulate ornamentation and warts
  • marginal cells U-shaped and bilobed
  • inner cells H-shaped
  • intercellular space lens-shaped or circular
  • chloroplast parietal
  • single pyrenoid
Pediastrum-duplex-var-asperum
Pediastrum duplex var. asperum

I found Pediastrum duplex var. asperum in October 2023 in the uppermost mud layer of the pond the convent Hegne. The main characteristic is the reticulate ornamention of the cell wall interspersed with warts. This can only be recognized at higher magnifications. However, the species can also be recognized at lower magnifications by the “rough” outline. Pediastrum duplex var. asperum only occurred sporadically in the samples. The population may be larger in the summer months.

Pediastrum-duplex-var-asperum

Fig. 1 a-b: Pediastrum duplex var. asperum. D = 72 µm. Two focal planes of a coenobium of 16 cells. Note the reticulate ornamention of the cell wall (b). Obj. 100 X.