GENERA starting with "M"

Symmetrical biraphid - The valves of Mastogloia are elliptical to elliptic-lanceolate or lanceolate, with rounded to capitate ends. The valvocopula (first girdle band) each possess complex silica chambers, called partecta, that function to secrete strands of mucilage. The raphe is straight or undulate. The axial area is narrow, with a slightly expanded central area. Living cells have two plastids. Mastogloia is primarily a marine genus. A few...

Symmetrical biraphid - Frustules of Mayamaea are small. The axial area is thickened and contains a straight raphe. Sometimes the axial area is all that remains from an acid preparation. The striae are uniseriate. Mayamaea includes the former Navicula atomus and its affiliates. Mayamaea species are found in ephemeral habitats as well as waters high in nutrient waste. Mayamaea species may reach high abundance in some polluted habitats.

Centric - Melosira valves have little ornamentation. They lack distinctive features including costae, septae, and spines. Frustules form long colonies linked at the valve face. Melosira contains a small number of freshwater species. M. varians, one of the most common species of the genus grows in benthic habitats of eutrophic streams and lakes. Melosira also contains the species M. undulata, which grows in large, oliogotrophic...

Araphid - Frustules of Meridion are club shaped in valve view and wedge shaped in girdle view. Septae (attached to girdle elements) are present. An apical porefield is present at one end. Valves may have 2 rimoportulae. Cells form fan-shaped colonies. Chloroplasts are multiple and plate-like in living cells. Meridion includes the common species, M. circulare and M. anceps. Some species have been considered as species of Diatoma,...

Symmetrical biraphid - Frustules of Microcostatus are small in size. The axial area includes lyre-shaped depressions on both sides of the prominent sternum. The depressions contain small costae (microcostae). Striae not visible with the light microscope. SEM reveals striae are present and comprised of single rows of areolae. In living cells two plastids are present, pressed to the cingulum. The genus contains the former Navicula krasskei...

Symmetrical biraphid - SPECIES OF MICROFISSURATA ARE NOT KNOWN TO OCCUR IN NORTH AMERICA Species are comparatively small and usually live as solitary cells. Valves are lanceolate or linear elliptical, with protracted ends. The axial area is wide or very wide, especially in the central area. The central area is an expanded fascia. Externally, the striae are open slits, termed microfissures. Internally, the microfissures are closed and covered...

Symmetrical biraphid - The outline of valves of Muelleria is linear, linear-elliptical or panduriform. The external proximal raphe ends are distinctive for their unilateral deflection. Distal raphe ends are branched. A longitudinal canal is present on each side of the raphe. Areolae are loculate. Living cells contain four plastids. Muelleria gibbula and M. terrestris appear to be widespread in aerophilic habitats, in association with soils,...