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(Last Modified On 1/29/2013)
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(Last Modified On 1/29/2013)
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Genus
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THEOBROMA L.
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Contributor
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JOSER CUATRECASAS
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PlaceOfPublication
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Sp. PI. 782. 1753
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Reference
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Cuatrecasas, Contr. U. S. Nat. Herb. 35: 449. 1964.
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Synonym
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Cacao Mill., Gard. Dict. Abridg. ed. 4. 1754. Tribroma Cook, Jour. Wash. Acad. Sci. 5: 288. 1915.
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Description
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Trees with primary branching 3- or 5-verticillate; further branching alternate; apical growth of the stem limited to the production of a whorl (jorquette) of 3-5 spreading, verticillate branches; continuing growth of the stem sympodial, by ad- ventitious, subterminal shoots (below jorquette) (called chupons) or by pseudo-- apical shoots (above jorquette) from buds axillary to the terminal verticillate branches. Leaves simple, long-petiolate and varied in phyllotaxy on the primary stem, short-petiolate and distichous on the lateral branches, penninerved or sub- palmatinerved, persistent, coriaceous or subcoriaceous; pluricellular trichomes usually as stellate hairs, rarely simple, sometimes glandular hairs. Inflorescences dichasial or monochasial, axillary or on reduced, tuberculiform branchlets on trunk and larger branches; pedicels articulate to bracteate peduncles. Flowers her- maphrodite; sepals 5, almost free and spreading or more or less united; petals 5, contorted, each one strangulated in 2 halves; lower part, corresponding to the claw, rigid and strongly veined with the shape of a hood; upper part a flat lamina, articu- lated to the inflexed apex of the claw; androecium in 2 whorls, united at base; outer whorl with 5 sterile, petaloid or linear staminodes opposite to the sepals; inner whorl with 5 fertile stamens opposite to the petals, the filaments short, shortly 2- to 3-branched, each branch with one anther; anthers hidden inside the petal- hoods, bithecate, the thecae unilocular and longitudinally dehiscent; pollen grains 3-colporate, peritreme, suboblate; gynoecium 5-carpellar, the ovary ovoid, pentag- onal, 5-celled with axile placentation; ovules many, in two rows, anatropous with two integuments and dorsal raphe; styles 5, free or more or less united, filiform; stigmas apical, short, acute. Fruit large, subbaccate or subdrupaceous, indehiscent, the pericarp fleshy or hard and partly woody or coriaceous, the vascular axis thin and vanishing; seeds usually in 5 rows, each seed surrounded by a thick, fibrosc, pulpy tissue filling the cavity at maturity, ovoid, ellipsoid or amygdaloid, the epi- sperm double, thick, subcoriaceous, the other layer with a trichomatic and gelat- inous epiderm developing into a thick, pulpy envelope; embryo straight; cotyledons thick, strongly plicate-corrugate; endosperm reduced to a filmy membrane covering the cotyledons; germination epigeous or hypogeous.
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Habit
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Trees
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Distribution
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A neotropical genus of 22 species of small or medium-sized trees, many of them endemics, usually growing in the tropical rain forests.
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Note
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Theobroma is important as a source of cacao beans which are produced mainly by one species, widely cultivated, T. Cacao. In Panama five species are known to be found at present.
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Key
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a. Leaves glabrous or puberulous beneath; jorquette 5-branched; petal-laminae stipitate, yellowish; staminodes narrowly subulate, red or purplish; stamens 2-antheriferous; fruit globose to fusiform and acute, more or less pentagonal or decagonal, glabrous, with carnose, relatively thick pericarp; flowers on trunk and on branches; growth below jorquette -.................... 3. T. CACAO aa. Leaves densely stellate-tomentose beneath; jorquette 3-branched. b. Leaves apparently glabrous and shining beneath, the indumentum, ho- motrichous, extremely minute and appressed in the areolae; inflorescences on trunk; petal-laminae sessile, crimson; staminodes lanceolate or subulate, purplish-red; stamens 2-antheriferous; fruit ellipsoid-oblong, more or less obtusely pentagonal, 15-20 x 6-7.5 cm., coriaceous; growth below jorquette -... ........... 2. T. BERNOULLII bb. Leaves clearly tomentose beneath; inflorescences on branches. c. Leaves elliptic-ovate or oblong-ovate, the lower surface silvery-green- ish or cinereous, covered with a dense layer of uniform, stellate hairs; petal-laminae subsessile, red, brownish-red or purplish; staminodes linear-oblong, obtuse or subacute, brownish-red; stamens 2-antherif- erous; fruit ellipsoid, 15-20 x 9-12 cm., with a thick-woody, strongly costate-reticulate and lacunose pericarp; growth below jorquette.....3. T. BICOLOR cc. Leaves obovate-oblong, elliptic-oblong or oblanceolate, heterotrichous beneath with dense, minute, whitish, stellate hairs and large, ochra- ceous or ferruginous, stellate hairs on the nerves; petal-laminae stipi- tate; staminodes oblong-obovate; stamens 3-antheriferous; pericarp coriaceous; growth above jorquette. d. Petal-laminae and staminodes yellow; fruit oblong-ellipsoid or ovoid-ellipsoid, umbilicate and 5-costate at base, slightly attenu- ate at apex, 10-18 x 6-9 cm., tuberculate-rugose; leaves cinereous beneath, the nerves with large, ochraceous, stellate hairs, these with long, spreading rays ..................- 4. T. ANGUSTIFOLIUM dd. Petal-laminae and staminodes brownish-red; fruit ellipsoid, rounded at both ends, about 7 x 4 cm., smooth; leaves cinereous beneath, the nerves with thick, ferruginous, stellate hairs, these with short rays -......................... 5. T. HYLAEUM
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