Penium spirostriolatum (Barker, 1869)
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Ibmer Moor (Austria)
Phylogenetic tree: Penium spirostriolatum
Diagnosis:
- cells cylindrically, attenuating gradualley to truncate or rounded apices
- length 80–400 µm
- cell wall with spiralized ridges
- 2–4 chlorplasts per cell
- chloroplasts with 6–7 longitudinal ridges and 1–3 pyrenoids
- pyrenoids somtimes elongated
- girdle bands present
- nucleus central
- terminal vacuoles in the apices absent
I found Penium spirostriolatum in June 1995 in the Ibmer Moor (Austria). The alga is not present in my local sites.
Penium spirostriolatum can easily be recognized by the 4 chloroplasts per cell, which are separated from each other by transverse gaps (s. fig. 1 b). The chloroplasts have 6-7 longitudinal ridgess, making them appear star-shaped in cross-section. The pyrenoids in the chloroplasts can sometimes have an elongated, stretched shape.
The similar species Closterium closteroides var. intermedium can also have 4 chloroplasts, which are separated by transverse gaps. However, this species has clear teminal vacuoles at the apices, in which crystals are visible, as is typical for the genus Closterium.
Fig. 1 a-b: Penium spirostriolatum. L = 160 µm. Two focal planes of a specimen frim the Ibmer Moor (Austria). Note the gaps between the 4 chloroplasts (arrows). Nu = nucleus. Obj. 40 X.