All Taxa

Mastogloiaceae: Mastogloia

Frustules isovalvar, isopolar (very rarely heteropolar in some marine species), bilaterally symmetrical. Cells seen in girdle or valve view.

Valve outline linear-lanceolate, lanceolate to elliptical, with rounded to capitate apices.

Striae uniseriate or occasionally biseriate, parallel or radiate; areolae variable and complex, often loculate (chambered). Striae can vary in arrangement across the valve (e.g. change from uniseriate to biseriate; be interrupted by lateral sterna creating lyre-like markings).

Axial area usually narrow; sometimes bearing ridges on either side of the raphe internally.

Central area variable: absent, round or transversely rectangular.

Raphe often with an undulate outer fissure; external central raphe endings simple or pore-like, sometimes curved (as a result of the undulate course of the outer fissure); internal central raphe endings simple or running into lipped (helictoglossa-like) structures; terminal fissures usually hooked.

The first (most advalvar) band (the valvocopula) with a unique structure, bearing a row of special bulbous chambers (‘partecta’) that open to the outside by simple apertures or oblique ducts and to the inside by fields of tiny pores.

Two, lobed chloroplasts lying ‘fore and aft’ (i.e. with one towards each pole) in the cell, each consisting of two valve-appressed X-shaped plates, connected by a wide bridge containing a pyrenoid.

Solitary or growing within mucilaginous masses secreted partly or wholly via the partecta, or producing discrete mucilage strands from the partecta; often attached.