Neidium iridis (Ehrenb.) Cleve (1894: 69)

Hamilton, Paul B., Savoie, Amanda M., Sayre, Cynthia M., Skibbe, Oliver, Zimmermann, Jonas & Bull, Roger D., 2019, Novel Neidium Pfitzer species from western Canada based upon morphology and plastid DNA sequences, Phytotaxa 419 (1), pp. 39-62 : 43

Neidium iridis (Ehrenb.) Cleve (1894: 69) Fig. 1

Individuals examined for morphology: n = 28, examined for molecular analysis: n = 2.

Frustules isovalvar. Valves linear to linear elliptic with narrowing obtuse to sagittate apices. Length 184–275 μm, 20.0–37.5 μm wide, 14–15 striae in 10 μm and 14–15 areolae in 10 μm. One large longitudinal canal present along each margin. Striae parallel at mid-valve, parallel to weakly convergent at apices ( Fig. 1 ). Axial area linear to linear elliptic from center to apex. Central area round to weakly elliptic, covers approximately 1/3–1/2 of mid-region of valve. In LM, raphe lateral with tightly curved proximal raphe ends and terminal fissures end at laciniae.

Observations:— Neidium iridis was found from a single locality (multiple samples) collected from VanDusen Botanical Garden, British Columbia, Canada. The species is identified by its plastid rbc L DNA sequence, large size relative to other Neidium taxa, one longitudinal canal along each margin and the sagittate shape of valve apices. Neidium iridis has a large size range (length, 184–275 μm) in this population which is comparable to N. iridis from the type locality and another locality in eastern North America ( Hamilton et al. 2019). N. iridis is comparable to N. beatyi but can be distinguished by the valve shape, valve size and number of longitudinal canals.

Figures

FIGURES 1–5. Neidium iridis (Fig. 1) and Neidium beatyi sp. nov. (Figs 2 (holotype), 3–5). Scale bar = 50 μm.