Pleurotaenium subcoronulatum f. elongatum Croasdale & A.M.Scott

Levanets, Anatoliy & Vuuren, Sanet Janse Van, 2024, New insights into the morphology, taxonomy and geographical distribution of Pleurotaenium subcoronulatum (Zygnematophyceae, Desmidiales), Phytotaxa 655 (2), pp. 144-158 : 150

2. Pleurotaenium subcoronulatum f. elongatum Croasdale & A.M.Scott in Prescott et al. 1975: 132; pl. XLIX [49]: fig. 5

Type locality: USA, Mississippi, pond 5.2 miles southeast of Mendenhall.

Description: Cells of P. subcoronulatum f. elongatum ( Fig. 4C ) are considerably longer than cells of the type ( Fig. 4A–B ). Cells are 21 times longer than wide, slightly undulated from the base to the apex. Twelve (12) rounded tubercles are visible at the apex. Cells are often arranged in the form of chains consisting of several cells that are easily separated. Length: 780–952 μm. Width: c. 44 μm. Width at apex: c. 36 μm.

Distribution:

North America: USA ( Prescott et al. 1975; Dillard 1990; Fairbanks 2020).

Asia: India ( Das & Keshri 2016).

Figures

FIGURE 4. Comparison of the morphology of P. subcoronulatum with closely related infraspecific taxa. A) P. subcoronulatum (from Turner 1893), B) P. subcoronulatum (from West & West 1895, C) P. subcoronulatum f. elongatum (from Prescott et al. 1975), D) P. subcoronulatum var. africanum (from Krieger 1937), E) P. subcoronulatum var. detum (from West & West 1896), F) P. subcoronulatum var. maximum (from Van Oye 1953), G) P. subcoronulatum var. rectum (from Borge 1903) and H) P. subcoronulatum var. spinulosum (from Opute 2000). No scale bars; dimensions indicated in descriptions.