Brachysira vitrea (Grunow) Ross

Kennedy, Bryan & Allott, Norman, 2017, A review of the genus Brachysira in Ireland with the description of Brachysira praegeri and Brachysira conamarae, new raphid diatoms (Bacillariophyceae) from high status waterbodies, Phytotaxa 326 (1), pp. 1-27 : 13

Brachysira vitrea (Grunow) Ross in Hartley ( Figs 52–60 )

Morphologically the outline is typically broadly elliptic-lanceolate with distinctly capitate poles.Valves with subcapitate ends ( Figs 52 & 59 ) were occasionally encountered. Valve dimensions (n=29): length 19.5–32 μm, width 5.5–7.5 μm

and striae density 32–36 in 10 μm. B. vitrea was found predominately in lakes. Although encountered across a broad alkalinity gradient, it occurred only at low densities (<0.7%) in near neutral lakes (pH=6.8) of low alkalinity (4.0

mg/l CaCO 3) and reached maximum abundance (1.4%) in higher alkaline calcareous lakes which were often marl precipitating (68–155 mg /l CaCO 3; pH: 8.0–8.1). Morphology and ecology conforms well to that outlined by Lange-Bertalot & Moser (1994) and Hoffmann et al. (2013).

Figures

FIGURES 52–60. Brachysira vitrea. Figs 52–56. LM. Figs 57–60. SEM. Scale bar = 10 μm for all LM figures. Scale bar in all SEM micrographs = 2 μm.