Theobroma L.
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Authority
Cuatrecasas, José. 1964. Cacao and its allies, a taxonomic revision of the genus Theobroma. Contr. U. S. Natl. Herb. 35: 379-614. pl. 1-12.
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Family
Malvaceae
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Scientific Name
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Type
Type.—Theobroma cacao L.
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Description
Description - Flowers hermaphroditic, pentamerous, pentacyclic, diplostemonous. Buds globose, ovoid or oblong-ovoid. Sepals 5, valvate in aestivation, almost free and spreading or more or less united in the lower part, cupular, or united by pairs into one single and two double lobes, or rarely in two lobes. Petals 5, dextrorsely contorted in aestivation, each one strangulated in two halves: 1) a lower part corresponding to the claw, rigid and strongly veined with the shape of a hood (cucullus); 2) an upper part, a flat blade (lamina), articulated to the inflexed apex of the claw. Androecium in two verticils of five, united in a tube at base: an outer whorl with 5 sterile, petaloid or linear staminodes, opposite to the sepals; an inner whorl with 5 fertile stamens opposite to the petals, the filaments short, minutely 2-3-branched, each branch with an anther. Anthers hidden inside the petal-hoods, bilobate (bithecate), the thecae unilocular and dehiscent by longitudinal clefts. Pollen grains 3-colporate, peritreme, suboblate (about 15-22 x 17.5-25 p). Gynoecium 5-carpellar, syncarpic, superior, the carpels opposite to petals, the ovary ovoid, pentagonal, 5-celled with axile placentation, the many ovules in two rows in each cell. Stylodes 5, connivent, free or more or less united, filiform. Stigmas apical, short, acute. Ovules anatropous with two integuments and dorsal raphe. Fruit large, subbaccate or subdrupaceous, indehiscent, ovoid, ellipsoid or oblong, obtuse or acute, smooth or ridged, rugose or tuberculate, the pericarp fleshy or hard and partly woody or coriaceous, the vascular axis thin and vanishing; seeds usually in five rows, each one surrounded by a thick, fibrose, pulpy tissue filling the cavity at maturity, ovoid, ellipsoid, or amygdaloid, the episperm double, thick, subcoriaceous, the outer layer with a trichomatic and gelatinous epiderm developing into a thick, pulpy envelope; embryo straight, the radicle cylindrical, inferior; cotyledons thick, strongly plicatecorrugate; endosperm usually reduced to a filmy membrane covering the cotyledons. Germination epigeous or hypogeous. Evergreen tree with the apical growth of the stem limited to the production of a terminal whorl of 3-5 spreading branches; sympodial growth of the stem attained by adventitious upright subterminal shoots or by pseudoapical shoots from buds axillary to the apical branching whorl. Primary branching of stem 3- or 5-verticillate, the further branching alternate. Leaves simple, entire, penninerved, persistent, coriaceous, long-petiolate and varied in phyllotaxy on the primary stems, short-petiolate and distichous on the branches. Inflorescences dichasial or monochasial (cincinate), axillary or on reduced tuberculiform branchlets on trunk and larger branches. Peduncles bracteate, articulate to pedicels. Pluricellular trichomes in all species, usually as stellate hairs, rarely simple. Globose, stipitate glands present in some species. Chromosome number: 2n=20.