SPECIES starting with "m"


Mastogloia calcarea

  1. Valve margins nearly parallel
  2. Apices rostrate
  3. Small central area, often asymmetric
  4. Raphe kinked near central area

Symmetrical biraphid - Valves normally linear-lanceolate. Apices normally rostrate. Central area small, commonly asymmetric, elliptic to irregular in shape. Raphe generally straight, but kinked near the central area. Proximal raphe ends deflected in the same direction. Striae punctate, slightly radiate, becoming almost parallel near the apices.

Mastogloia elliptica

  1. Partecta all of same size
  2. Striae uniseriate
  3. Raphe branches sinuous

Symmetrical biraphid - Valves are elliptic to linear-elliptic with bluntly rounded ends. Partecta are all the same size. Striae consist of single rows of coarse areolae. Raphe branches are sinuous (not straight).

Mastogloia grevillei

Mastogloia smithii var. grevillei

  1. Valve linear-lanceolate
  2. Raphe undulate
  3. Striae biseriate

Symmetrical biraphid - Valve linear-lanceolate with apices protracted and rounded. The raphe is lateral, reverse lateral about midway from the apices to the central area. Striae are radiate and biseriate.

Mastogloia lacustris

  1. Valves linear-lanceolate
  2. External proximal raphe ends enlarged
  3. Width 8-10 µm

Symmetrical biraphid - Valves linear-lanceolate, with margins slightly convex to nearly straight. The apices are bluntly produced. The raphe is straight and filiform, becoming lateral at about ½ the way between the apex and central area. The proximal raphe ends are enlarged. Striae are distinctly punctate and radiate, except at the apices where they are parallel.

Mastogloia pumila

  1. Lateral sterna present
  2. Central partecta larger than distal partecta
  3. Striae uniseriate
  4. Raphe straight

Symmetrical biraphid - Valves are linear-lanceolate to elliptic-lanceolate with subtly protracted and broadly rounded apices, lateral sterna, and partecta of two different sizes. The striae are uniseriate and the raphe is straight, rather than sinuous.

Mastogloia smithii

  1. Valves elliptical-lanceolate
  2. Protracted apices
  3. Valvocopulae with locules
  4. Striae 15-18 in 10 µm

Symmetrical biraphid - Valves elliptic-lanceolate with protracted, broadly rounded apices. The raphe is filiform, becoming lateral at about ½ from the apices to the center. Striae are radiate and distinctly punctate.

Mastolgoia pseudosmithii

  1. Valve elliptic-lanceolate
  2. Apices rostrate
  3. Raphe with median kink
  4. Striae slightly radiate

Symmetrical biraphid - Valves are elliptical-lanceolate. Apices are normally rostrate, but round in small cells. Central area is elliptic to polygonal in shape. Raphe is generally straight but with a median kink. Proximal raphe ends are expanded. Striae are slightly radiate, becoming parallel at the apices.

Melosira undulata

  1. Cells large, cylindrical, and robust
  2. Striae conspicuous
  3. Mantle unevenly thickened
  4. Mantle rimoportulae evenly-spaced

Centric - Melosira undulata has large, robust, cylindrical frustules linked in long chains. Valves and mantles are conspicuously ornamented with rimoportulae and striae. A ring of evenly-spaced rimoportulae encircles the mantle near the valve/mantle interface. The mantle is unevenly thickened internally, giving an undulating appearance.

Melosira varians

  1. Cells cylindrical, forming filaments of linked cells
  2. Valve face and margin with little to no ornamentation

Centric - Cells cylindrical, often forming long chains. Valve face slightly convex, covered with very small spines. Unlike many Aulacoseira species, valves lack areolae.

Meridion circulare

  1. Valves linear-clavate
  2. Costae present
  3. Narrow sternum
  4. Single rimoportula

Araphid - Valves linear-clavate, asymmetric to the transapical axis. Costae are present running transversely across the valves. A narrow sternum extends the length of the valve. A single rimoportula is located near the headpole.

Meridion circulare var. constrictum

  1. Valves linear-clavate
  2. Headpole distinctly rostrate
  3. Costae present
  4. Sternum narrow
  5. Single rimoportula

Araphid - Valves are clavate, with a rostrate headpole. Costae extend transversely across the valve. A single rimoportula is present near the headpole. The sternum is narrow.

Meridion lineare

  1. Valves slightly heteropolar
  2. Forms ribbon-like colonies
  3. Costae perpendicular to apical axis
  4. Striae 16-18 in 10 µm

Araphid - Valves are slightly heteropolar, with ovoid to linear-lanceolate margins. Frustules typically attach to one another in long ribbon-like colonies. Transapical costae are mostly perpendicular to the apical axis and number 4-6 in 10 µm. Striae are distinct and number 16-18 in 10 µm.