Mitreola L.

Scientific Description

Family Loganiaceae.

Habit and leaf form. Herbs. Annual, or perennial. Leaves cauline. To 0.025–0.3 m high. Mesophytic. Not heterophyllous. Leaves minute, or small; opposite; decussate; petiolate, or sessile; simple. Leaf blades dorsiventral; entire; ovate, or elliptic; pinnately veined; cross-venulate. Mature leaf blades adaxially glabrous, or pubescent; abaxially glabrous, or pubescent. Leaves with stipules (well developed or reduced to a transverse ridge). Stipules interpetiolar. Leaf blade margins entire.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes. Inflorescences terminal, or axillary (or both); dichasial with long 1-sided botryoidal branches. Flowers pedicellate, or subsessile; minute; more or less fragrant; regular; 5 merous; tetracyclic. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; scarcely gamosepalous; lobed; lobulate. Calyx lobes markedly longer than the tube. Calyx glabrous (mostly), or hairy (sometimes outer surface minutely papillose); regular; persistent. Corolla present; 5; 1 -whorled; gamopetalous; lobed; lobulate. Corolla lobes about the same length as the tube (or slightly shorter). Corolla imbricate (quincuncial), or valvate (in M. minima and M. turgida); urceolate; regular; hairy abaxially (on lobes); hairy adaxially (on lobes and with penicillate hairs or pilose ring in throat); plain; white, or yellow, or purple (i.e. mauve). Androecial members definite in number. Androecium 5. Androecial members adnate; all equal; free of one another; 1 -whorled. Stamens 5. Staminal insertion near the base of the corolla tube. Stamens all inserted at the same level; isomerous with the perianth; oppositisepalous; all alternating with the corolla members. Filaments glabrous. Anthers all alike; basifixed; dehiscing via longitudinal slits. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; eu-syncarpous; partly inferior. Ovary plurilocular; 2 locular. Gynoecium stylate. Styles 2; partially joined (distinct at base but united in the stigma); attenuate from the ovary; apical. Stigmas 1; 2 - lobed; capitate. Placentation axile. Ovules c. 30 per locule.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule. Dispersal unit the seed. Fruit 40–50 seeded (‘many’). Seeds endospermic.

Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia and Northern Territory. South-West Botanical Province. A genus of c. 6 species; 1 species in Western Australia; 1 endemic to Western Australia.

Etymology. A diminutive of the Greek mitra; refers to the mitre-shaped capsule.