Citation: Rudge, Trans. Linn. Soc. 10:300 (1811).

Derivation: Greek trakhys, rough; mene, moon; alluding to the appearance of the fruit.

Synonymy: Didiscus DC. ex Hook., Curtis's Bot. Mag. 55:t. 2875 (1828). About 45 species mainly in Australia (about 35 species), some in Malesia, New Caledonia and Fiji.

Common name: None

Description:
Annual or biennial herbs, some with a perennial rootstock, glabrous or pubescent; tap-roots slender or thick; stem branched, smooth-cylindrical or sometimes faintly striate; basal leaves petiolate, palmatisect or ternately divided, rarely entire and 3-5-lobed, with glandular, dendroid or simple hairs, rarely glabrous; stem leaves less divided, from deeply 3-lobed to the uppermost entire, ovate to linear; petioles sheathing.

Umbels simple, pedunculate, terminal or leaf-opposed; involucral bracts narrow-linear, often shortly connate at the base; flowers mostly numerous; sepals minute, subulate; petals white, pink or blue, obovate, entire, straight at the apex, imbricate in bud.

Fruit laterally compressed, notched at the base; carpophore undivided, persistent; mericarps flat, semicircular, smooth, glabrous, villous or tuberculate; dorsal rib prominent, sometimes winged; intermediate ribs curved and often semicircular; lateral ribs at the commissure; the 2 mericarps of 1 fruit often unequal in the structure of their surface, sometimes 1 aborted; vittae absent.

Biology: No text

Key to Species:

1. Small annuals; umbels with 3-12 flowers
2. One mericarp of 1 fruit smooth or granular, the other muricate	T. pilosa 5.
2. Both mericarps of 1 fruit with the same surface
3. Fruit with flat ciliolate bristles	T. cyanopetala 2.
3. Fruit with woolly intricate hairs	T. ornata 4.
1. Coarse erect annuals or biennials; umbels with 50 or more flowers
4. Plant hairy	T. anisocarpa 1.
4. Plant glabrous and glaucous	T. glaucifolia 3.

Author: Not yet available