SPECIES starting with "H"

Asymmetrical biraphid - Valves are strongly dorsiventral. The raphe is positioned near the ventral margin. Proximal raphe ends weakly inflated with slight deflection dorsally. A dorsal fascia is absent, and the dorsal striae are uninterrupted. Valve ends are protracted, narrowly rostrate to subcapitate.

Asymmetrical biraphid - Valves are semi-lanceolate. Valve ends are protracted, narrowly rostrate and bent ventrally. The raphe is located near the middle of the valve, gently arched, with proximal raphe ends with slight dorsal deflection. Axial area narrow. The central area on dorsal side forms a thickened semi-stauros extending to valve margin. Dorsal and ventral striae difficult to resolved in LM.

Asymmetrical biraphid - Valve apices are protracted, capitate, and ventrally curved. The raphe is located near the valve midline, with sharply deflected proximal ends. The axial area is narrow on the dorsal side and extends nearly to the valve margin on the ventral side. A fascia present on the dorsal side forming a thickened semi-stauros, ventral fascia absent. Dorsal striae interrupted longitudinally, ventral striae composed of a single row of very short areolae along the entire ventral margin.

Asymmetrical biraphid - Valves are semi-lanceolate and strongly dorsiventral. Valve ends are protracted and capitate.The proximal ends are widely spaced. The axial area is narrow throughout. Dorsal and ventral fascia are absent. Dorsal striae are punctate and radiate throughout. Ventral striae are continuous.

Asymmetrical biraphid - Valves are small, 9-13 µm in length and broadly semi-elliptical to semi-circular. Valve apices are protracted and capitate. The raphe is straight. The axial area is narrow at the poles, widening to form a lanceolate central area. Dorsal striae are composed of a single areola.

Asymmetrical biraphid - Valves are semi-lanceolate and strongly dorsiventral. Valve ends are rostrate and ventrally curved. The raphe is positioned near the ventral margin. Axial area is narrow. Dorsal and ventral fascia are absent. Dorsal striae are distinctly punctate, more so in the central area, and radiate throughout.

Araphid - Apices are capitate to attenuate. Dorsal margin is highly arched and convex, the ventral margin is concave with a unilateral swelling of the central area. The central sternum is distinct and narrow. A rimoportula is present near the valve ends and is often visible in the light microscope. Striae are parallel.

Symmetrical biraphid - Valves are elliptical-lanceolate with capitate to subcapitate apices. The striae are biseriate, 8-11 in 10 μm. A hyaline area is present at each end of the valve.

Symmetrical biraphid - Valves are rhombic-lanceolate with slightly drawn-out apices. The striae are biseriate and number 10-11 in 10 μm. A hylaine area and one apical row of areolae are present at each end of the valve.

Symmetrical biraphid - Valves are lanceolate with subrostrate apices. The striae are uniseriate, slightly radiate to parallel in the valve center, slightly convergent at the apices and number 11-13 in 10 μm. A hyaline area and one apical row of areolae are present at each end of the valve.

Symmetrical biraphid - Valves are elliptical-lanceolate with rounded apices. The striae are biseriate and number 8-11 in 10 μm. A hyaline area and one or two apical rows of areolae are present at each end of the valve.

Symmetrical biraphid - Valves broadly linear to nearly elliptical in outline. Raphe short, with the distal ends not reaching the apices. The proximal raphe ends terminate quite a distance from one another. Striae distinct and radiate.