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SPECIES starting with "b"


Bacillaria paradoxa

  1. Valves linear to linear-lanceolate
  2. Keel placed along center of valve

Nitzschioid - Valves are isopolar, linear to linear-lanceolate, sometimes with slightly undulate margins, tapering to narrow apices. The keel is located in the center of the valve.

Biremis circumtexta

  1. Valves lanceolate
  2. Axial area wide, lanceolate
  3. Striae marginal
  4. Areolae visible under LM
  5. On one side of valve, a row of areolae next to raphe

Symmetrical biraphid - Valves are lanceolate with slightly protracted apices. The axial area is wide and lanceolate. Areolae within striae are easily observed under LM. A longitudinal row of areolae is adjacent to the raphe slits on the primary valve side. A conopeum is visible as a longitudinal line crossing the striae.

Biremis undulata

Oestrupia zachariasii var. undulata

  1. Valves with a central expansion
  2. Apices cuneate
  3. Striae coarse, with 3 dash-like areolae
  4. Longitudinal canal marginal

Symmetrical biraphid - Valves with a large central expansion and weakly tri-undulate margins. Apices are cuneate. Striae are coarse and composed of three transapically elongate areolae. A marginal longitudinal canal connects outer two areolae of each stria.

Boreozonacola hustedtii

  1. Valves triundulate
  2. Striae radiate in middle
  3. Central area circular

Symmetrical biraphid - Boreozonacola hustedtii has triundulate valves with a circular central area. Striae are radiate in the middle.

Boreozonacola olympica

  1. Valve margin parallel or slightly concave
  2. Striae parallel in central area
  3. Central area small, elliptic

Symmetrical biraphid - Valves are linear, with parallel or slightly concave sides. Striae are parallel in the center part of the valve. The central area is small and elliptic.

Brachysira arctoborealis

  1. Valves rhombic
  2. Valves large
  3. Striae 24-26 in 10 µm

Symmetrical biraphid - Valves are large, rhombic and up to 48 µm long and 12 µm wide. Striae number 24-26 in 10 µm.

Brachysira brebissonii

Anomoeoneis serians var. brachysira

  1. Valves rhombic-lanceolate to elliptical-lanceolate
  2. Striae weakly radiate
  3. Raphe positioned within two longitudinal ribs
  4. Papillae may be present or absent

Symmetrical biraphid - Valves are rhombic-lanceolate to elliptical-lanceolate in valve outline. Striae are weakly radiate across the entire valve face. The raphe is positioned within two external ribs on the valve face. The ribs terminate at the edge of the central area and the apices. The areolae are irregular in shape and spacing, creating a “wave-like” appearance of the striae. The orientation and size of areolae, creates a series of wavy longitudinal hyaline zones. Central area is small and circular to slightly oval. Valves may vary in the development of external ribs.

Brachysira hannae

  1. Rhombic valve with straight sides
  2. Length to width ratio 2:1 to 3:1
  3. Alternating long and short striae near the central area

Symmetrical biraphid - Valves are rhombic with straight margins. The valve length is two to three times the valve width. Within each stria, the orientation and irregular size of the areolae creates a wavy appearance of the striae. Striae at the center valve margin are short, and not interrupted.

Brachysira microcephala

  1. Valves with subcapitate to capitate apices
  2. Central striae radiate
  3. Central area small, asymmetrically rounded
  4. Areola shape variable

Symmetrical biraphid - Valves are lanceolate to rhombic-lanceolate with protracted, subcapitate to capitate apices. The central striae are radiate at the center, to parallel at the apices. Areolae are variable in shape and arranged in a series of two to three longitudinal hyaline zones. The central area is small and asymmetrically rounded.

Brachysira neoacuta

  1. Valves narrowly lanceolate
  2. Striae strongly radiate at the center
  3. Areolae distinctly rectangular
  4. Distal raphe unilaterally curved

Symmetrical biraphid - Valves are narrowly lanceolate, with a length to width ratio of approximately 5:1. The striae are strongly radiate at the center, becoming parallel at the apices. Irregular striae are present near the central area. Areolae are distinctly rectangular and range 2-4 per stria. The distal raphe is distinctly unilaterally curved.

Brachysira ocalanensis

  1. Valves lanceolate to linear-lanceolate
  2. Apices narrowly rounded, subrostrate, or subcapitate
  3. Central area a narrow ellipse
  4. Striae >31 in 10 µm

Symmetrical biraphid - Brachysira ocalanensis has lanceolate to linear-lanceolate and occasionally heteropolar valves. Apices are narrowly rounded, subrostrate, or weakly subcapitate. The central area is a narrow ellipse with the long dimension oriented apically. Striae number more than 31 in 10 µm.

Brachysira serians

Anomoeoneis serians
Navicula serians

  1. Valves lanceolate
  2. Striae slightly radiate to parallel
  3. Central area asymmetrically rounded
  4. Raphe straight at distal valve

Symmetrical biraphid - Valves are lanceolate. The striae are slightly radiate to parallel. The axial area is linear and distinct. The central area is asymmetrically rounded. The raphe is positioned between two external longitudinal ribs. The raphe is straight with undifferentiated proximal fissures and deflexed T-shaped distal fissures. Areolae are rectanglular and elongated in the transapical axis.

Brachysira styriaca

Anomoeoneis styriaca

  1. Valves lanceolate
  2. Central area elongate and constricted in larger valves
  3. Apices not protracted

Symmetrical biraphid - Valves are lanceolate with unprotracted apices. The central area is apically elongate, with a median constriction, a feature most pronounced in the largest valves. Striae number 26-30 in 10 µm.

Brachysira vitrea

Anomoeoneis vitrea

  1. Valves elliptic-lanceolate
  2. Apices capitate
  3. Striae 32-36 in 10 µm

Symmetrical biraphid - Brachysira vitrea has broadly elliptic-lanceolate valves with capitate apices. Striae number 32-36 in 10 µm.

Brachysira zellensis

  1. Valves linear
  2. Central area large
  3. Longitudinal line present

Symmetrical biraphid - Valves are linear, with bluntly rounded apices. The central area is large. A single, wavy longitudinal line is evident on each side of the raphe. Striae number 30-32 in 10 µm.

Brebissonia lanceolata

  1. Valves symmetrical, lanceolate
  2. Striae in the center parallel, becoming radiate toward the ends
  3. Central nodule elongate
  4. Apical pore fields present

Asymmetrical biraphid - Brebissonia lanceolata has large lanceolate to lanceolate-elliptic valves, with slightly protracted, broadly rounded to attenuate ends. Striae are parallel in the center of the valve, becoming radiate toward the ends. The elongate central nodule results in a large gap between proximal raphe ends.