Micromelum Blume
Bijdr.Fl.Ned.Ind. 3:137 (1825)

Name Status: Current
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Scientific Description
H.R. Coleman, Thursday 8 September 2016

Family Rutaceae.

Habit and leaf form. Small trees, or shrubs; evergreen, or deciduous; bearing essential oils. Plants unarmed. Mesophytic, or xerophytic. Leaves alternate; spiral; ‘herbaceous’; petiolate; non-sheathing; gland-dotted; aromatic; compound; usually pinnate, or unifoliolate, or ternate; imparipinnate. Leaflets 5–23. Lateral leaflets alternate. Leaflets ovate, or oblong, or elliptic. Leaf blades pinnately veined, or one-veined; without cross-venules. Leaves without stipules, or with stipules. Stipules when present, intrapetiolar; represented by glands. Leaf blade margins entire, or crenate, or serrate, or dentate. Leaves without a persistent basal meristem. Leaf anatomy. Hairs present; complex hairs absent (trichomes simple). Stem anatomy. Nodes unilacunar, or tri-lacunar. Secondary thickening developing from a conventional cambial ring.

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

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. Inflorescence many-flowered. Flowers in cymes, or in corymbs. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal, or axillary; usually large, terminal corymbose panicles often flat-topped, often surrounded by leaves much larger than even the largest inflorescences. Flowers pedicellate; bracteate; small to medium-sized; malodorous (foetid); regular, or somewhat irregular. The floral asymmetry when noticeable, involving the perianth and involving the androecium (not K). Flowers 5 merous; cyclic. Floral receptacle developing a gynophore (associated with the disk), or with neither androphore nor gynophore. Free hypanthium absent. Hypogynous disk present; intrastaminal; annular (sometimes one-sided), or of separate members. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx 5; 1 -whorled; gamosepalous; lobed; hairy; imbricate; cupuliform; regular; with the median member posterior. Corolla 5; 1 -whorled; polypetalous; valvate; regular, or unequal but not bilabiate; densely hairy abaxially; green, or white, or yellow. Petals linear, or oblong. Androecium 10. Androecial members unbranched, or branched (? by the splitting of simple primordia); free of the perianth; markedly unequal; free of one another, or coherent; 1 - adelphous, or 3–12 - adelphous; 1 -whorled, or 2 -whorled. Stamens 10; diplostemonous; alternisepalous; filantherous. Filaments glabrous. Anthers sub basifixed; versatile; dehiscing via longitudinal slits; introrse, or latrorse; tetrasporangiate. Gynoecium 2–6 carpelled. The pistil 2–6 celled. Gynoecium syncarpous; synovarious, or synstylovarious, or eu-syncarpous; superior, or partly inferior, or inferior. Ovary plurilocular; (2–)3–5(–6) locular; sessile. Gynoecium stylate. Styles 1, or 3–5; free, or partially joined; apical; much longer than the ovary at anthesis; deciduous (caducous after anthesis); thinly hairy. Stigmas wet type, or dry type; papillate, or non-papillate; Group II type, or Group IV type. Placentation axile. Ovules 2 per locule; pendulous to ascending; epitropous; superposed; arillate, or non-arillate; anatropous, or hemianatropous.

Fruit and seed features. Fruit 6–10 mm long; fleshy, or non-fleshy; yellow, or orange, or red; indehiscent; a berry (with twisted locules); 1–3 seeded. Seeds oblong; endospermic, or non-endospermic. Embryo well differentiated. Cotyledons 2. Embryo chlorophyllous, or achlorophyllous; straight, or curved, or bent. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C3.

Geography, cytology, number of species. A genus of 10 species.

Taxonomic Literature

  • Wheeler, J. R.; Rye, B. L.; Koch, B. L.; Wilson, A. J. G.; Western Australian Herbarium (1992). Flora of the Kimberley region. Western Australian Herbarium. Como, W.A.