[1] The type locality is on the slopes of Gifberg, a mountain forming part of the eastern boundary of the Olifants River Valley.

The specific epithet "toximontana" is a Latin translation of the Afrikaans name of the mountain.

[2] Isoetes toximontana is an herb which grows in shallow water, very often emerging above the surface.

Leaves are 3-10 per plant, up to 42 mm long, elliptical in cross-section.

Megaspores number up to 36 per sporangium, gray-green, drying olive green, each up to 320 μm in diameter, covered with tubercules (bumps) over most of the surface.