Desmidium elegans (Raciborski) Grönblad

Araújo, Camila Barbosa de, Bicudo, Carlos Eduardo de Mattos, Takiyama, Luís Roberto & Melo, Sérgio de, 2020, Pseudofilamentous desmids (Zygnematophyceae) from an Amazonian floodplain lake (Macapá, AP, Brazil), Iheringia, Série Botânica (e 2020010) 75, pp. 1-14 : 5

Desmidium elegans (Raciborski) Grönblad , Acta Societatis Scientiarum Fennicae: ser. B, 2(6): 34, pl. 15, fig. 331-333. 1945.

Hyalotheca elegans Raciborski , Flora, Jena 81: 31, pl. 3-4, fig. 1. 1895.

( Figs. 7 A-B)

Cells 1-2 times greater in length than width, 24-44 × 18-19 μm, 10-17 μm broad at the apex and 16-22 μm broad at the isthmus. Semicells pyramidal-truncated; straight apical margins; lateral margins slightly concave; apical and basal angles that were sub-rectangular-rounded; shallow median constriction; open median sinus; hyaline cell wall; axial chloroplast.

Material examined: BRAZIL, AMAPÁ, Macapá, Curralinho Lake , 02.VI.2007, C.B. Araújo (SP469217), 03.VII.2007, C.B. Araújo (SP469218), 12.II.2008, C.B. Araújo (SP469224), 15.IV.2008, C.B. Araújo (SP469226), 13.V.2008, C.B. Araújo (SP469227), 15.VII.2008, C.B. Araújo (SP469228) .

Comments: the cell wall of this species showed some variation between smooth or finely punctuated to punctuated with pores that were arranged in decussing series (Bicudo & Samanez 2016). However, it was not possible to observe the series of pores close to the semicell apex in any of these individually analyze specimens. According to the literature, the species may sometimes show variation in the measurements of pseudofilaments, as some specimens are slender and some others more robust. The present specimens were morphologically similar, and their measurements were comparable to those in Grönblad (1945: fig. 332).

Distribution in Brazil: Amazonas (Förster 1974, Souza & Melo 2010); Bahia ( Oliveira 2011); Goiás ( Dias & Sophia 1994); Pará ( Grönblad 1945, Scott et al. 1965); São Paulo ( Bicudo & Samanez 1984, 2016); Federal District ( Leite & Senna 1992).

Figures

Figs. 3-15. Pseudofilamentous desmids of Curralinho Lake, Macapá, Amapá, Brazil. 3 A-C. Bambusina borreri. A, B. detailed cells; C. detailed pseudofilament; 4. B. borreri var. brasiliensis; 5 A-B. B. borreri var. majus, detailed cells and pseudofilaments; 6. Desmidium baileyi var. baileyi f. bailey; 7 A-B. D. elegans. A. detailed pseudofilament, B. detailed cell; 8 A-B. D. graciliceps var. graciliceps. A. frontal view of the pseudofilament, B. slight modification of the pseudofilament frontal view; 9. D. graciliceps var. groenbladii; 10 A-C. D. longatum. A. pseudofilament frontal view, B. formation of the elongate conjugation tube, C. zygospore; 11 A-B. D. quadratum var. quadratum. A. detailed pseudofilament, B. detailed cells; 12. D. quadratum var. constrictum; 13 A-B. Groenbladia neglecta var. neglecta. A. detailed pseudofilament, B. detailed cells; 14 A-B. G. neglecta var. elongata. A. detailed pseudofilament, B. detailed cells; 15. Haplozyga armata var. armata. Scale bars = 10 µm.