Xanthosoma Schott
  • H.W.Schott & S.L.Endlicher, Melet. Bot.: 19 (1832) 


Notes: Distribution: Mexico to Trop. America

General Description

Terrestrial; caudex tuberous and subterranean or growing over the surface of the ground and rooting at the lower nodes, the apical portion erect, stout; sap with white latex; petioles amplexicaule, conspicuously sheathed at the base, subterete above the sheath, moderately spongy; blades moderately thin; sagittate, hastate, trisect or pedatisect; midrib sunken above, prominently raised below; primary lateral. veins of the blades or their segments spreading toward the margins, forming several collective veins; tertiary veins conspicuous. INFLORESCENCES 1-several per axil, much shorter than the leaves; spathe convolute at base, tube usually green, sometimes tinged along the open margin with purple, constricted somewhat above the tube; tube mostly ellipsoid, persistent after anthesis; the blade moderately thin, usually white naviculiform at anthesis, promptly deciduous after anthesis; spadix shorter than the spathe, divided into pistillate and staminate portions; the pistillate portion basal, cylindric, densely many-flowered, slightly tapered toward the apex, green to bright orange; staminate portion clavate, usually several times longer than the pistillate portion, slightly constricted above the sterile portion at the base; sterile staminate portions with irregularly shaped sterile staminate flowers, these usually elongated in the direction of the axis. Flowers unisexual, naked; staminate flowers irregularly 4-6-sided, the stamens 4-6, connate to form an obpyramidal truncate synandrium; anthers with thecae obversely oblong-triangular or oblong, opening at the apex of the connective by a short slit; ovaries oblong, to ovoid, coherent by the thickened annuliform styles, 2-4 celled; ovules several or numerous, anatropous; stigma discoid or hemi-spheric-discoid, 3-or 4 lobate. INFRUCTESCENCES with berries cylindroid, 3-4 celled; seeds many per locule, ovoid, shorter than the funicles, testa sulcate.

Latex milky. HABIT : small to gigantic, sometimes arborescent, evergreen or seasonally dormant herbs, stem either a thick, subcylindric, hypogeal tuber often producing smaller tubers on stoloniferous side branches or often with a distal, epigeal, massive, arborescent upper part, or an entirely hypogeal subglobose tuber, bearing many very small tubercles in some spp. (X. pubescens, X. viviparum), tuber sometimes yellow within. LEAVES : several, rarely pubescent. PETIOLE : sheath usually rather long. BLADE : cordate, sagittate, hastate, trifid, trisect, pedatifid or pedatisect, rarely linear-lanceolate to ovate with emarginate base, rarely peltate; basal ribs well-developed, often denuded proximally, primary lateral veins pinnate, forming submarginal collective vein, 1 or more distinct marginal veins also present, secondary and tertiary laterals arising from the primaries at a wide angle, forming interprimary collective vein, higher order venation reticulate. INFLORESCENCE : 1 to many in each floral sympodium, always appearing with leaves. PEDUNCLE : usually rather short, rarely long. SPATHE : strongly constricted, tube with convolute margins, ovoid to ellipsoid, usually ventricose, rather thick-walled in large species, persistent, blade boat-shaped-oblong to -oblong-lanceolate, gaping and erect or sometimes reflexed at anthesis, marcescent after anthesis and then deciduous. SPADIX : shorter than spathe, densely flowered, female zone cylindric-conoid, often obliquely inserted onto peduncle, separated from male zone by longer, conoid to attenuate, basally thicker zone of sterile male flowers, male zone cylindric-conoid, longer than female zone, usually fertile to apex, rarely with a few sterile flowers at extreme apex. FLOWERS : unisexual, perigone absent. MALE FLOWER : 4-6-androus, connate into a truncate-obpyramidal, subpentagonal or hexagonal synandrium, anthers lateral, nearly reaching base of synandrium, common connective thick, thecae obversely oblong or tapering basally, dehiscing by subapical pore or short slit. POLLEN : extruded in strands, shed in tetrads, inaperturate, ellipsoid to subspherical, medium-sized (mean 42 µm., range 35-49 µm., tetrads :- mean 76 µm., range 62-97 µm.), exine minutely punctate- or fossulate-verruculate. STERILE MALE FLOWER : composed of obpyramidal truncate, laterally compressed synandrodes, lowermost larger, uppermost narrower and more elongated (in sense of spadix axis). FEMALE FLOWER : ovary ovoid, 2-4-locular, more rarely 1-locular, ovules (12-)20 to very numerous, anatropous or hemianatropous, funicles rather long, placentae usually pseudoaxile, or sometimes parietal or axile basally, style broader than ovary, usually discoid-thickened coherent to weakly connate with those of neighbouring flowers, rarely free and swollen (X. plowmanii), stigma subhemispheric or 2-4-lobed, yellow, narrower than style. BERRY : cylindric, somewhat furrowed apically, whitish to orange, many-seeded. SEED : ovoid, testa costate, embryo axile, subequal to endosperm, endosperm copious.

Diagnostic Description

Small to gigantic terrestrial, evergreen or seasonally dormant herbs with milky latex, stem tuberous and hypogeal or aerial and erect; leaf blade usually cordate or sagittate to pedatisect, submarginal collective vein present, fine venation reticulate; spathe strongly constricted, tube persistent, blade deciduous after flowering; spadix male and female zones separated by conspicuous zone of sterile flowers, fertile to apex; flowers unisexual, perigone absent; male flower a truncate synandrium. Differs from Chlorospatha in having a subglobose, inflated spathe tube, female zone of spadix free from spathe, styles normally discoid (laterally swollen) and coherent (except Xanthosoma plowmanii ), synandrodes (sterile flowers) between male and female flowers well-developed, ± prismatic.

Habitat

Tropical moist and humid forest, subtropical forest; geophytes on forest floor, in wet places, swamps, river banks, seasonally flooded sites, grassy places, plantations, some species are weedy.

Distribution

Species ca. 57, Mexico to Paraguay.

Mexico to Trop. America.

Uses

X. sagittifolium and its many varieties are important subsistence food plants throughout the humid tropics of the world due to their starch- and protein-rich tuberous stems (see chapter 15).

Literature

in Schott & Endl., Melet. 1: 19 (1832); Engl., Pflanzenr. 4, 23 E: 41 (1920).

Distribution Map

 
  • Native distribution
  • Introduced distribution
Specimens
Found in
  • Northern America Mexico Mexico Central
  • Mexico Gulf
  • Mexico Southeast
  • Mexico Southwest
  • Southern America Brazil Brazil North
  • Brazil Northeast
  • Brazil South
  • Brazil Southeast
  • Brazil West-Central
  • Caribbean Cuba
  • Dominican Republic
  • Haiti
  • Jamaica
  • Leeward Is.
  • Puerto Rico
  • Trinidad-Tobago
  • Windward Is.
  • Central America Belize
  • Costa Rica
  • Guatemala
  • Honduras
  • Nicaragua
  • Panamá
  • Northern South America French Guiana
  • Guyana
  • Suriname
  • Venezuela
  • Southern South America Argentina Northwest
  • Paraguay
  • Western South America Bolivia
  • Colombia
  • Ecuador
  • Peru
Introduced into
  • Africa South Tropical Africa Zimbabwe
  • West Tropical Africa Benin
  • Guinea
  • Guinea-Bissau
  • West-Central Tropical Africa Gabon
  • Gulf of Guinea Is.
  • Zaire
  • Asia-Tropical Indian Subcontinent Bangladesh
  • Malesia Borneo
  • Christmas I.
  • Malaya
  • Australasia Australia Norfolk Is.
  • Northern America Southeastern U.S.A. Alabama
  • Pacific North-Central Pacific Hawaii
  • South-Central Pacific Cook Is.
  • Easter Is.
  • Society Is.
  • Southwestern Pacific Gilbert Is.
  • Niue
  • Southern America Caribbean Cayman Is.
  • Venezuelan Antilles

Included Species

  Bibliography

  • 1 Govaerts, R. & Frodin, D.G. (2002). World Checklist and Bibliography of Araceae (and Acoraceae): 1-560. The Board of Trustees of the Royal Botanic Gardens, Kew.
  • 2 F.n. Hepper (1968) Araceae. Flora of West Tropical Africa 3(1)
  • 3 Goncalves, E.G. The Commonly Cultivated Species of Xanthosoma Schott (Araceae), including Four New Species. Aroideana; Journal of the International Aroid Society 34, 23 (2011).
  • 4 Gardens, K.""Royal Bot World Checklist of Selected Plant Families. (2008).
  • 5 Mayo, S.J., Bogner, J. & Boyce, P.C. The Genera of Araceae. (Royal Botanic Gardens Kew: 1997).

 Information From

CATE Araceae
http://araceae.e-monocot.org
Haigh, A., Clark, B., Reynolds, L., Mayo, S.J., Croat, T.B., Lay, L., Boyce, P.C., Mora, M., Bogner, J., Sellaro, M., Wong, S.Y., Kostelac, C., Grayum, M.H., Keating, R.C., Ruckert, G., Naylor, M.F. and Hay, A., CATE Araceae, 14 Dec 2011 . 17 Dec 2011.
  • A All Rights Reserved
Flora of West Tropical Aftrica (FWTA)
http://kew.org/efloras/
Royal Botanic Gardens, Kew, 2004. eFloras: Iridaceae. [online] Available at: http://kew.org/efloras/ [Accessed 2013-08-02]
  • B All Rights Reserved
  • C http://creativecommons.org/licenses/by-nc-sa/3.0/
Global Biodiversity Information Facility
http://data.gbif.org
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eMonocot
http://e-monocot.org
eMonocot. (2010, 1st November). Retrieved Wednesday, 8th February, 2012, from http://e-monocot.org.
  • E Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
World Checklist of Selected Plant Families
http://apps.kew.org/wcsp/
WCSP 2014. 'World Checklist of Selected Plant Families. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://apps.kew.org/wcsp/ Retrieved 2011 onwards
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