(Last Modified On 3/18/2013)
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(Last Modified On 3/18/2013)
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Genus
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Cnidoscolus Pohl
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PlaceOfPublication
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PI. Brasil. Icon. Descr. 1: 56, 1827, nom. cons. prop.
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Description
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Tree, shrubs, or herbs; monoecious; stems and leaves containing milky latcx and armed with stinging hairs. Leaves alternate; petioles long, glandular at junc- tion with blade; stipules usually present; palmately (rarely pinnately) veined, mostly palmately lobed, sometimes deeply parted and nearly compound. Inflo- rescences terminal (sometimes pseudo-axillary) dichasia, the pistillate flowers at the lower (proximal) nodes, the staminate at upper nodes; flowers with more or less petaloid calyx, usually white; apetalous. Staminate flowers with calyx gamo- sepalous, lobes imbricate in bud; disc annular; stamens 8-10(-25), the outer free and the inner connate (or all connate); pollen grains globose, periporate, clavate; filiform staminodes (pistillodes?) sometimes present atop staminal column. Pistil- late flowers with calyx chorisepalous, the sepals deciduous (or gamosepalous in some species); disc annular, sometimes with staminodes; ovary of 3 (rarely 5) carpels, the ovules 1 per locule, the styles ? free, several times bifid or laciniate (rarely once bifid), sometimes apically dilated. Fruits capsular (rarely drupace- ous); seeds carunculate, with copious endosperm, the embryo straight, the cotyle- dons broad and longer than radicle.
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Habit
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Tree, shrubs, or herbs
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Distribution
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An American genus of about 50 species, the majority in Mexico and Brazil.
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Note
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Although earlier confounded with Jatropha, Cnidoscolus is much closer to Manihot, which it resembles in its apetalous flowers and periporate pollen grains. Cnidos- colus is unique, however, in its armament of painfully stinging hairs. The single native species, C. urens, belongs to an herbaceous complex in sect. Jussieuia (Houst.) Pax & Hoffmann.
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Reference
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MeVaugh, R., The genus Cnidoscolus: generic limits and intrageneric groups. Bull. Torrey Bot. Club 71: 457-474, 1944.
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Key
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a. Herbaceous or only slightly woody, 0.5-2 m high; stems and leaves heavily armed with stinging hairs; leaves 3-5-lobed, lobes finely denticulate; petiolar gland of many small digitiform processes; pistillate flowers only 3-6 per inflorescence, sepals ca 3 mm long, styles incrassate ......................... 1. C. urens aa. Arborescent shrub or tree, mostly 3-8 m high or more; stems and leaves (except sometimes for petioles and leaf-veins) nearly unarmed; leaves mostly 7-lobed, lobes coarsely and sharply again lobed; petiolar gland entire; pistillate flowers up to 20-30 per inflorescence, sepals 5-7 mm long, style-tips very slender . .. ..... 2. C. aconitifolius
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