Herbs, subshrubs, or shrubs [trees], annual or perennial, monoecious or dioecious; hairs stellate or scalelike; latex colorless to reddish [absent]. Leaves persistent, semideciduous, or drought deciduous, alternate, simple, often with lemony, pungent, or acrid odor when crushed, older leaves often turning orange before falling; stipules absent or present, persistent, deciduous, or caducous; petiole present [absent], glands present at apex or absent; blade unlobed [palmately lobed], margins entire, crenate, denticulate, serrulate, or serrate-dentate, laminar glands absent [at base, on margins or abaxial surface]; venation pinnate or palmate at base, pinnate distally. Inflorescences unisexual or bisexual (pistillate flowers proximal, staminate distal), terminal or axillary, spikes, racemes, or thyrses; glands subtending each bract 0. Pedicels present or absent. Staminate flowers: sepals (3–)5(–6), valvate or slightly imbricate, distinct or connate basally; petals (3–)5(–6) or 0, distinct, white; nectary extrastaminal, usually 5 glands; stamens 3–35[–50], inflexed in bud, distinct; pistillode absent. Pistillate flowers: sepals [3–](4–)5(–9)[–10] or 0, imbricate or valvate, distinct (connate for 1/2+ length in C. argyranthemus); petals 5 (sometimes rudimentary) or 0, distinct or connate basally, white or pale green; nectary annular, 5 glands, or absent; pistil (1–)3-carpellate; styles (1–)3, distinct or connate basally, unbranched, 2-fid, or multifid. Fruits usually capsules (achenes in C. michauxii). Seeds ellipsoid, oblong, ovoid, globose, or lenticular; caruncle present. x = 8, 9, 10, 14.
CROTON L.
Por Grady L. Webster
Arboles, arbustos o hierbas, con tricomas, al menos en parte, estrellados o lepidotos, sin látex; plantas monoicas o raramente dioicas. Hojas alternas o subopuestas debajo de las inflorescencias terminales, simples, a veces palmadamente lobadas, pinnatinervias o palmatinervias; pecioladas, muy frecuentemente estipuladas, frecuentemente glandulares. Flores en racimos o espigas terminales o axilares; flores estaminadas con sépalos mayormente 5, imbricados o valvados, pétalos 5 o raramente ausentes, imbricados, disco entero o disecado, estambres mayormente 850, libres, filamentos inflexos en la yema, pistilodio ausente; flores pistiladas sésiles o pediceladas, sépalos mayormente 57, imbricados o valvados, enteros o dentados, pétalos 5 ó ausentes, disco generalmente entero o lobado, ovario 3-locular, 1 óvulo por lóculo, estilos libres o casi así, bífidos o bipartidos a multífidos. Fruto capsular; semillas carunculadas.
Género tropical y subtropical con ca 1000 especies, mejor representado en América; 28 especies se conocen en Nicaragua y 1 más se espera encontrar.
G.L. Webster. A provisional synopsis of the sections of the genus Croton (Euphorbiaceae). Taxon 42: 793823. 1993.
Hierbas, arbustos o árboles, monoicos o (rara vez) dioicos, con indumento generalmente de tricomas simples, estrellados o escamiformes, la savia incolora o (más frecuente) coloreada (anaranjada o rojiza); estípulas ausentes o (más frecuente) presentes, pequeñas, usualmente deciduas. Hojas alternas, el pecíolo usualmente con glándulas en el ápice; lámina simple, lobulada o (mucho más frecuente) no lobulada, de otra forma entera o aserrada. Infls. terminales o axilares, bisexuales o (rara vez) unisexuales, espigadas o racemosas, a veces paniculadas o subcapitadas, usualmente con las fls. pistiladas (1 por nudo) proximales y las estaminadas (1–numerosas por nudo) distales, o ambas mezcladas en los nudos. Fls. estaminadas con disco anular o disecado; sépalos 4–6(–10), imbricados o valvados; pétalos 5 (ausentes en C. punctatus); estambres 8–50, los filamentos curvados en el botón; pistiloide ausente. Fls. pistiladas con disco entero o lobulado; sépalos 4–10, imbricados o valvados; pétalos 5 (a veces reducidos o ausentes); ovario (2)3-locular; óvulos 1 por lóculo; esti- los ± separados, una vez a muchas veces bífidos. Frs. capsulares; semillas lisas o levemente rugulosas, carunculadas.
Trees or shrubs, rarely subshrubs, monoecious or more rarely dioecious; latex clear or reddish, often scanty or apparently absent; indumentum of stellate hairs and/or peltate scales. Leaves alternate, rarely opposite or nearly verticillate; stipules present or absent; petiole with or without apical paired glands; leaf blade simple, margin entire or denticulate, often with glands; venation pinnate or palmate. Inflorescences terminal or axillary, racemelike thyrses, often with proximal solitary female flowers and distal male flowers, often in clusters. Male flowers: sepals mostly 5, imbricate to valvate, free; petals 5, smaller or nearly equal to sepals; disk glandular, usually 5, and opposite sepals; stamens 10-20; filaments free, inflexed in bud; anthers muticous; pistillode absent. Female flowers: sepals 5, often narrower than in male, imbricate to reduplicate-valvate, persistent, sometimes accrescent; petals 5, smaller than in male, mostly reduced or obsolete; disk annular or dissected, receptacle often villous; ovary 3-locular; ovules 1 per locule; styles 3, longer and slender, free or nearly so, once to several times bifid. Fruit a capsule dehiscing into 3 2-valved cocci, more rarely ± indehiscent and fleshy, drupelike or berrylike. Seeds usually smooth, carunculate; testa crustaceous; endosperm copious, fleshy; cotyledon broad and flattened.
Trees, shrubs, or herbs; monoecious or dioecious; stems usually with colored sap, the indumentum (at least in part) stellate or lepidote. Leaves alternate; petiolate (petioles often with glands near the top); stipulate (stipules sometimes obscure or obsolete); blades pinnately or palmately veined, sometimes lobed, entire or serrate. Inflorescences spicate-racemose (or sometimes paniculate or subcapitate), terminal or axillary; bisexual racemes mostly with 9 flowers solitary at proximal nodes, male 1-several at distal nodes (sometimes at same nodes with female). Staminate flowers with 4-6 imbricate or (most often) valvate calyx-lobes; disc entire or dis- sected; petals usually 5 (rarely absent); stamens mostly 8-50, free, the filaments inflexed in bud; pollen grains globose, inaperturate, clavate; pistillode absent. Pistillate flowers with 4-10 (mostly 5-7) imbricate or valvate calyx-lobes; disc usually entire, rarely dissected, sometimes with staminodia; petals 5, often reduced or absent; ovary of 3 (rarely 2) carpels, the ovules 1 per locule; the styles more or less free, once to repeatedly bifid or bipartite. Fruits capsular; seeds terete to compressed, dry, carunculate, endosperm present, the embryo with broad cotyledons.
Inflorescences terminal, sometimes axillary, racemose or spicate, with the flowers sometimes in fascicles or glomerules on the spike, rarely paniculate, androgynous, with the ♀ flowers usually below the ♂’s, or unisexual; bracts small, caducous or persistent
Male flowers: sepals (4–)5(–6), valvate or imbricate, ± equal; petals usually present, (4–)5(–6), rarely more, free, equalling or shorter than (rarely longer than) the sepals; disc-glands small, opposite the sepals, free or fused, fleshy, rarely 0; stamens central, 5–many, free, inserted on a usually pilose receptacle, the filaments inflexed in bud, later erect, the anthers pendulous in bud, later erect, longitudinally dehiscent; pistillode 0
Seeds smooth or more rarely rugulose, generally triangular-convex in transverse section, carunculate, with a woody or crustaceous testa and abundant fleshy albumen; embryo straight; cotyledons broad and flat.
Female flowers: sepals often narrower than in ♂, generally persistent and slightly accrescent, equal or unequal; petals often smaller and/or narrower than in ♂, or vestigial or 0, rarely replaced by tufts of hairs; staminodes sometimes present; disc annular or composed of separate glands, sometimes scarcely developed; ovary (2–)3(–4)-locular, with 1 ovule per locule; styles 1–several times bifid or bipartite, rarely laciniate
Fruits dehiscent, septicidally into 3 bivalved cocci, or loculicidally into 3 valves, or sometimes drupaceous or berry-like, and then subindehiscent; endocarp woody or crustaceous
Leaves alternate or sometimes subopposite or subverticillate on the same shoot, simple, entire or toothed, rarely lobed (not in E. Africa), penninerved or 3–many-nerved from the base, petiolate, usually with two (sometimes more) sessile or stalked discoid glands at the base of the blade, generally stipulate, often turning bright yellow or red when dying
Monoecious or more rarely dioecious trees, shrubs or, more rarely, herbs or lianes, with an indumentum of stellate hairs or peltate scales, separately or in combination
Inflorescences usually terminal, racemose, androgynous or unisexual; bracts small.
Leaves alternate, sometimes subopposite or ± whorled, stipulate, petiolate, with 2 or more sessile or stipitate discoid glands at the petiole apex or the lamina base, simple, entire, toothed or lobed, penninerved or palminerved.
Female flowers pedicellate; sepals generally persistent, slightly accrescent, equal or unequal; petals often smaller than in male flowers, sometimes replaced by tufts of hairs or absent; staminodes sometimes present; disk annular, or of separate glands, or vestigial; ovary 2(3)4-locular, with 1 ovule per loculus; styles 1–several times bifid or bipartite, or multifid or multipartite.
Male flowers shortly pedicellate; buds subglobose; sepals (4)5(6), valvate or imbricate, ± equal; petals (4)5(6), free; disk glands opposite the sepals, free or fused, fleshy; stamens 5–many, free, filaments inflexed in bud, later erect, anthers pendulous in bud, later erect, longitudinally dehiscent; receptacle usually pilose; pistillode absent.
Monoecious or sometimes dioecious trees or shrubs (or herbs or lianes outside the Flora Zambesiaca area) with a stellate and/or lepidote indumentum.
Seeds carunculate; testa woody or crustaceous; albumen fleshy, copious; embryo straight; cotyledons broad and flat.
Fruits septicidally dehiscent into 3 bivalved cocci, loculicidally dehiscent into 3 valves, irregularly frangent (breaking up) or drupaceous and indehiscent; endocarp woody or crustaceous.
Arbres , arbustes, rarement plantes herbacées ou lianes, monoïques ou plus rarement dioïques; présence fréquente de poils étoilés ou de poils écailleux peltés suborbiculaires ou de poils écailleux portant en leur centre une touffe de poils dressés (poils écailleux-étoilés) parfois réduite à un seul poil central.'Feuilles'alternes ou parfois opposées ou verticillées sur le même rameau, simples, entières ou dentées, rarement lobées, penninerves ou tri- à multinervées à la base, pétiolées, assez souvent parsemées de ponctuations translucides, généralement munies ± au niveau limbe-pétiole de 2 glandes ordinairement disciformes, indurées, sessiles ou pédonculées; stipules généralement présentes.'Inflorescences'terminales, parfois axillaires, en racèmes, en épis ou en épis de fascicules ou de glomérules 1- à pauciflores, rarement en panicules, androgynes ou unisexuées; bractées caduques ou persistantes.'Fleurs'♂ à (4)5(6) sépales valvaires à ± imbriqués ou encore ouverts à la base et imbriqués au sommet, généralement égaux; pétales (4)5(6-15), généralement présents, libres, de même longueur ou plus courts que les sépales; glandes du disque oppositisépales, libres ou soudées, charnues, rarement nulles; étamines centrales, 5 à très nombreuses, libres, insérées sur un réceptacle ordinairement indumenté (toujours au Congo); filets incurvés dans le bouton, puis dressés; anthères à déhiscence longitudinale; rudiment d'ovaire nul.'Fleurs'♀ à (4)5(6-12) sépales souvent plus étroits que les ♂, ordinairement persistants et un peu accrescents, égaux ou inégaux; pétales généralement plus petits que les ♂, souvent rudimentaires ou nuls, rarement représentés par une touffe de poils; staminodes parfois présents; disque annulaire ou composé de glandes, parfois peu développé; ovaire (2)3(4)-loculaire, généralement couvert de poils étoilés; styles 1 à plusieurs fois bifides ou bipartis, rarement laciniés; ovule 1 par loge.'Capsules'septicides à 3 coques bivalves ou loculicides à 3 valves munies en leur milieu de portions de cloisons, parfois drupes ou baies; endocarpe lignifié ou crustacé.'Graines généralement caronculées et triangulaires-convexes en coupe transversale; spermoderme crustacé ou lignifié; albumen abondant, charnu; embryon droit; cotylédons larges et plans.\n\t\t\t\tGenre comprenant près de 900 espèces dans les régions tropicales et subtropicales, la plupart américaines; environ 50 espèces africaines continentales; 21 espèces au Congo, dont 2 insuffisamment connues2.\n\t\t\t\tDiverses espèces sont signalées dans la pharmacopée, notamment'C. tiglium L., petit arbre originaire d'Asie tropicale, parfois cultivé au Congo (Eala) et dont les graines fournissent une huile purgative et révulsive.\n\t\t\t\tLes fruits de plusieurs'Croton congolais demeurent inconnus; le mode de déhiscence des fruits de la plupart des espèces congolaises demande à être observé sur le terrain.\n\t\t\t\tDiverses espèces sont utilisées comme arbres d'ombrage dans les plantations ou dans les villages indigènes.
Nearly 1000 species have been described in this natural but polymorphic genus. The majority of the species are American, but most of these occur in South America and the West Indies; about 80 distinct species have been recognized in continental North America.
SELECTED REFERENCES Berry, P. E. et al. 2005. Molecular phylogenetics of the giant genus Croton (Euphorbiaceae sensu stricto) using ITS and trnL–F DNA sequence data. Amer. J. Bot. 92: 1520–1534. Ferguson, A. M. 1901. Crotons of the United States. Rep. (Annual) Missouri Bot. Gard. 1901: 33–73. van Ee, B. W. and P. E. Berry. 2010. Taxonomy and phylogeny of Croton section Heptallon (Euphorbiaceae). Syst. Bot. 35: 151–167. van Ee, B. W. and P. E. Berry. 2009. The circumscription of Croton section Crotonopsis (Euphorbiaceae), a North American endemic. Harvard Pap. Bot. 14: 61–70. van Ee, B. W., R. Riina, and P. E. Berry. 2011. A revised infrageneric classification and molecular phylogeny of New World Croton (Euphorbiaceae). Taxon 60: 791–823. Webster, G. L. 1993. A provisional synopsis of the sections of the genus Croton (Euphorbiaceae). Taxon 42: 793–823.
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[Greek kroton, tick, alluding to resemblance of seeds] |
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Paul E. Berry "Croton Linn. in Flora of North America @ efloras.org" eFlora. Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA., 2017. Web. Accessed February 2018.