Family Muntingiaceae

Muntingiaceae C. Bayer, M.W. Chase and M.F. Fay

~ Elaeocarpaceae, Tiliaceae

Habit and leaf form. Small to medium trees and shrubs. Leaves alternate; distichous; petiolate; non-sheathing; simple. Lamina entire; basally conspicuously asymmetric to not conspicuously asymmetric; palmately veined; cross-venulate; asymmetrically cordate. Leaves stipulate (at least in Muntingia and Dicraspidia). Stipules intrapetiolar; free of one another (or one missing); on the plagiotropic branches of Muntingia and Dicraspidia peculiar: in the former, the ‘upper’ stipule of each leaf is narrow and the ‘lower’ is lacking, while in the latter the upper is large, peltate and leaflike while the lower is filiform. Lamina margins serrate. Leaves without a persistent basal meristem.

Leaf anatomy. Hairs present; eglandular and glandular (in combination); multicellular. Unicellular hairs branched and unbranched (in combination). Multicellular hairs branched and unbranched. Complex hairs present; stellate.

Lamina dorsiventral; without secretory cavities. The mesophyll not containing mucilage cells.

Stem anatomy. Secretory cavities absent. Cork cambium present. Secondary thickening developing from a conventional cambial ring. Xylem with fibre tracheids. Vessels without vestured pits. Wood semi-ring porous to diffuse porous; partially storied (VPI, Muntingia); parenchyma apotracheal.

Reproductive type, pollination. Plants hermaphrodite. Floral nectaries present. Nectar secretion in Muntingia from the disk (‘from behind the filaments at the base of the ovary’). Pollination entomophilous; via hymenoptera (Muntingia, by bees).

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or solitary and aggregated in ‘inflorescences’ (solitary and in few-flowered clusters in Muntingia); displaced axillary. Inflorescences displaced axillary (the flower- or inflorescence-subtending leaf subtending a vegetative bud as well: cf. Tiliaceae). Flowers medium-sized to large (‘relatively large’); regular; cyclic, or partially acyclic (?). The androecium acyclic (?). Floral receptacle developing an androphore, or with neither androphore nor gynophore (?). Free hypanthium absent. Hypogynous disk present; annular.

Perianth with distinct calyx and corolla; (8–)10(–14); 2 whorled; isomerous. Calyx (4–)5(–7); 1 whorled; basally gamosepalous; blunt-lobed, or toothed; regular; non-fleshy; persistent, or not persistent; non-accrescent; valvate (the tips free in Muntingia). Corolla (4–)5(–7); 1 whorled; polypetalous (the petals exceeding the calyx); imbricate and crumpled in bud; regular; white, or pink, or yellow (Dicraspidia and Neotessmannia); deciduous (thin). Petals with irregular margins.

Androecium (11–)15–100 (‘many’). Androecial members branched (‘many’ and ‘free or almost so’, suggesting ‘trunk bundles’ .....); maturing centrifugally; free of the perianth; free of one another, or coherent (tending to be bundled?). Stamens (11–)15–100 (‘many’); polystemonous. Anthers more or less basifixed, or dorsifixed; versatile, or non-versatile; dehiscing via short slits (at least sometimes, in Neotessmannia and Dicraspidia?), or dehiscing via longitudinal slits. Microsporogenesis simultaneous. Tapetum glandular. Pollen shed in aggregates (Neotessmannia), or shed as single grains; when shed in aggregates, in tetrads. Pollen grains 2-celled.

Gynoecium 5 carpelled, or 6–7 carpelled. Carpels isomerous with the perianth, or increased in number relative to the perianth (?). The pistil 5–35 celled (? — to many-celled via ‘false septa’). Gynoecium syncarpous; eu-syncarpous; superior (Muntingia), or partly inferior (Dicraspidia), or inferior (Neotessmannia). Ovary 5–7 locular (at least below). Locules secondarily divided by ‘false septa’ (commonly), or without ‘false septa’. Gynoecium non-stylate (almost, in Muntingia), or stylate. Styles 1 (thick); apical. Stigmas 1 (‘decurrent or lobed-sulcate’); 1 lobed, or 5–7 lobed. Placentation apical (the placentas pendulous and free from the apices of the locules, lobed). Ovules differentiated; 25–50 per locule (‘many’); pendulous; epitropous; with ventral raphe; anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle. Endothelium differentiated. Endosperm formation nuclear. Embryogeny onagrad.

Fruit fleshy; indehiscent; a berry; 25–100 seeded (‘many’, the seeds embedded in pulp). Seeds endospermic; small. Cotyledons 2. Embryo straight.

Physiology, biochemistry. Sugars transported as sucrose (Muntingia).

Geography, cytology. Neotropical. Tropical. Neotropical, with Muntingia introduced elsewhere.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Malvales. Cronquist’s Subclass Dilleniidae; Violales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Malvales.

Species 3. Genera 3; Dicraspidia, Muntingia, Neotessmannia.

From the incomplete and fairly unsatisfactory descriptive data provided by Bayer et al. (1998), here supplemented for ‘esoteric’ characters from the usual sources (see References). Neotessmannia is poorly known, and is now dubiously associated with the other two genera, which have long been acknowledged as anomalous members of Elaeocarpaceae or Tiliaceae (even referred to Flacourtiaceae by Cronquist). The displaced-axillary flower and inflorescence buds are less peculiar than Bayer et al. seem to suggest: see Rendle 1930 for discussion and interpretation of the bud pairs in Tiliaceae.

Economic uses, etc. Edible fruit from Muntingia, which is cultivated as an ornamental.