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LM image scalebar = 10 µm = pixels not measured
Observations
| Observations: | Bart Van de Vijver |
|---|---|
| Length: | 23-30µm |
| Width: | 9 10,5µm |
| Striae: | 14-16 striae in 10µm |
Description:
Valves elliptical-lanceolate with rounded rostrate apices (L 23-30µm, W 9 10,5µm, 14-16 striae in 10µm). Striae are composed of 3-4 rows of areolae. RV: axial area fairly narrow, linear. Central area large, rectangular, bordered by an irregular (2-5) number of shorter striae (irregularity even within the same valve). Raphe straight. ARV: characterized by a typical U-shaped sinus (present in the entire A. lanceolata complex), interrupting the normal striation pattern. Internally (SEM view) this sinusoidal marking appears as a circular depression.
| Morphology: | Monoraphid |
|---|---|
| Distribution: |
Autecology:
Notes:
Commonly reported from small, slightly acid pools with low specific conductance values (max.<100µS/cm). Also found in circumneutral, semi-dry (± 50%) soils. Mean F value in moss vegetation is 3,5±1,8.Kerguelen (Le Cohu & Maillard 1983, Van de Vijver et al. 1998a, 2001), Macquarie Island (McBride et al. 1999)Heiden described in 1928 a valid taxon (i.e. Achnanthes cyclophora) from some marine sediments that he considered to be a freshwater taxon whose valves had been washed into the sea. Since then, the taxon has been forgotten for quite a long time. Several years later, A. lanceolatoides was described by Sovereign, now transferred to the genus Planothidium. A detailed analysis however, pointed out that both taxa are conspecific and that A. cyclophora had priority. Since this taxon clearly shows all features of Planothidium, a transfer was necessary.
Other sites with Planothidium cyclophorum
- Ile de la Possession (moist habitats), Crozet Archipelago
Original Type Description
| Author: | Heiden 1992 |
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| Length: | |
| Width: | |
| Striae: |
Original Description:
New combination
| Author: | Van de Vijver |
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Citations
Index Nominum Algarum (INA):
- Original
- If an INA link is available, it will be shown above
- The INA is a bibliographic reference "card file" for algal taxonomy, containing nearly 200,000 names of algae (in the broad sense).
