Citation: Hook. fi, Fl. Tasm. 2:78 (1858).

Derivation: Greek treis, three; thyris, window; referring to the dehiscence of the fruit of T. submersa.

Synonymy: Not Applicable

Common name: None

Description:
Subaquatic annuals; rootstock minute, not forming a rhizome.

Capitula heterogamous, with the male florets scattered among a larger number of female florets; involucral bracts 2-8, lanceolate, spreading or erect, forming an apparent whorl below the florets; ovary more or less trigonous.

Fruit shortly pedicellate, with 3 prominent longitudinal ribs.

Distribution:  3 species endemic to Australia.

Biology: No text

Author: Not yet available