FIGURES 59–66. Type material of Rhoicosphenia lowei from Ash Creek, Lassen County, California, USA. SEM. 59–62. External views of R-valve show the bluntly rounded head pole, lineolate areolae, and dilated proximal raphe ends. The apical pore field has porelli that are more densely arranged, smaller, and rounder than the stria areolae (62). The distal raphe ends on R-valve continue onto the mantle (60, 62). 63–66. Internal R-valve shows the valvocopula is modified to overlap with the pseudosepta at each end of valve (63, 65, 66). The internal proximal raphe ends are strongly crook-shaped in the same direction (64). Scale bars are 10 μm (59), 1 μm (60–66).

Published as part of Thomas, Evan W. & Kociolek, J. Patrick, 2015, Taxonomy of three new Rhoicosphenia (Bacillariophyta) species from California, USA, pp. 1-21 in Phytotaxa 204 (1) on page 9, DOI: 10.11646/phytotaxa.204.1.1, http://zenodo.org/record/13638966