Habit and leaf form. Shrubs (with the bark of older stems in papery layers); evergreen; bearing essential oils. Plants with neither basal nor terminal concentrations of leaves; to 2–5 m high. Leptocaul. Mesophytic, or xerophytic. Leaves small to medium-sized; alternate (or scattered); leathery; petiolate; gland-dotted; aromatic; edgewise to the stem, or with ‘normal’ orientation; simple; epulvinate. Leaf blades dorsiventral, or isobilateral, or centric; entire; flat, or solid (in L. sulcata); terete (with 5 grooves); linear, or lanceolate, or oblong, or ovate; ovate, or oblong; pinnately veined, or parallel-veined, or one-veined; cross-venulate, or without cross-venules. Leaves without stipules; without a persistent basal meristem. Stem anatomy. Secondary thickening developing from a conventional cambial ring.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous, or ornithophilous. Pollination mechanism unspecialized.
Inflorescence and flower features. Flowers solitary (on the old wood); pedicellate; bracteolate, or ebracteolate; small to medium-sized; somewhat irregular to very irregular; zygomorphic. The floral asymmetry involving the androecium. Flowers 5 merous; cyclic. Free hypanthium present (petals ‘inserted on the calyx’); campanulate; hirsute. Hypogynous disk present. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; lobed; imbricate; exceeded by the corolla; regular; not persistent. Calyx lobes elliptic, or ovate. Corolla present; 5; 1 -whorled; polypetalous; imbricate; regular; hairy abaxially; glabrous adaxially; plain; orange, or yellow to green, or red; deciduous. Petals oblong, or obovate. Androecial members indefinite in number. Androecium 50–75. Androecial members branched. Androecial sequence determinable, or not determinable. Androecial members maturing centripetally; free of the perianth; markedly unequal; coherent; 1 - adelphous (connate into a short, slightly downcurved, unequally 5-lobed tube). Stamens 50–75; becoming exserted; polystemonous; alternisepalous; all opposite the corolla members; erect in bud, or inflexed in bud. Filaments not geniculate; hairy. Anthers dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate; appendaged, or unappendaged. Gynoecium 3 carpelled. The pistil 3 celled. Gynoecium syncarpous; eu-syncarpous; inferior, or partly inferior. Ovary plurilocular; 3 locular. Ovary summit hairy, the hairs not confined to radiating bands. Epigynous disk present, or absent. Gynoecium stylate. Styles 1; simple; from a depression at the top of the ovary; apical; becoming exserted; hairless. Stigmas 1; capitate. Placentation axile. Ovules 50 per locule (i.e. ‘many’); ascending (in the peltate placenta); non-arillate; anatropous.
Fruit and seed features. Fruit 8–12 mm long; subsessile to sessile; persistent; non-fleshy (woody); dehiscent, or indehiscent; a capsule, or a berry, or a drupe, or a nut. Capsules if capsular, septicidal, or loculicidal, or denticidal, or circumscissile. Fruit few-seeded. Seeds non-endospermic; oblong-cuneate; small; winged, or wingless. Cotyledons 2.
Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia and Northern Territory. Eremaean Botanical Province and South-West Botanical Province.
Etymology. After Je'rome Fre'de'ric Lamarche (b.1779), first lieutenant of Uranie on Freycinet's voyage round the world 1817–20.