Description: Annual or perennial herbs.
Leaves decussate or rosette forming, ± sessile; lamina 1- or 3–5-veined from base; margins entire.
Inflorescence terminal and/or axillary, cymose, often reduced to 1 flower. Flowers bisexual, usually 4-merous. Calyx tube about as long as lobes; lobes 4. Corolla urceolate, campanulate or trumpet-shaped, often bearded in mouth; lobes ± valvate in bud. Stamens inserted in lower half of corolla tube. Ovary superior. Styles 2, usually free at base, connate distally; stigma truncate to 2-lobed.
Fruit a septicidal capsule (dehiscing along the ventral suture), apically 2-horned (persistent bases of styles); seeds many, minute.
Distribution and occurrence: World: c. 55 species, Asia, Malesia, Australia, New Caledonia. Australia: c. 50 species (c. 44 species endemic), all States.
Text by B. J. Conn, edited by K.L. Gibbons June 2019
Taxon concept:
| | Key to the species | |
| 1 | Branches coarsely and densely hirsute, with long, more or less spreading hairs | 2 |
| Branches glabrous or sparsely and shortly hairy; hairs more or less appressed | 3 |
| 2 | Plant prostrate or procumbent; inflorescence 1-flowered | Mitrasacme pilosa |
| Plant erect; inflorescence umbellate, 3–5-flowered
Back to 1 | Mitrasacme polymorpha |
| 3 | Inflorescence 1- or 2-flowered | 4 |
| Inflorescence umbellate, 3–5-flowered
Back to 1 | 5 |
| 4 | Flowers almost sessile; corolla c. 2 mm long; perennial herb, prostrate or procumbent | Mitrasacme serpyllifolia |
| Flowers with pedicel up to 12 mm long; corolla 5–7 mm long; annual herb, mostly erect
Back to 3 | Mitrasacme alsinoides |
| 5 | Capsule 1.4–2.5 mm long; fruiting style <0.5 mm long, often bulbous below the stigma | Mitrasacme paludosa |
| Capsule 4–6 mm long, fruiting style 1.5–1.8 mm long, never bulbous below the stigma
Back to 3 | Mitrasacme pygmaea |
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