Zea mays |
Zea mays subsp. parviglumis |
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corn, cultivated corn |
Balsas teosinte, corn, Guerrero teosinte |
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Habit | Plants annual. | |||||||||||||
Culms | (0.5)1-3(6) m tall, (0.5)1-5 cm thick. |
(0.5)2-4 m, unbranched or branched above the middle, thinner than in subsp. mexicana. |
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Leaves | pubescent. |
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Blades | mostly 30-90 cm long, 2.5-12 cm wide. |
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Caryopses | concealed in fruitcases (wild taxa) or exposed (domesticated taxon); fruitcases of wild taxa distichous, triangular in side view; domesticated taxon without fruitcases, glumes reduced and shallow or collapsed and embedded in the rachis. |
concealed. |
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Pistillate | inflorescences rames or spikes, usually shortly pedunculate (sometimes sessile), solitary, 4-30(40) cm long, (0.5)1-10 cm thick, with 2 or more rows of paired spikelets, hence the spikelets 4 or more ranked, rarely terminating in an unbranched staminate inflorescence. |
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Staminate | panicles 10-25+ cm, with 1-60(235) branches, internodes 1.5-8.2 mm; spikelets 9-14 mm long, 2.5-5 mm wide; lower glumes rounded dorsally, flexible, translucent, papery, loosely enclosing the upper glumes, the 2 lateral veins subequal to the others, not winged. |
panicles with (2)10-100(235) slender, often drooping branches; spikelets 4.6-7.2 mm, distant. |
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Fruitcases | 5-8 mm long, 3-5 mm wide. |
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2n | = 20. |
= 20. |
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Zea mays |
Zea mays subsp. parviglumis |
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Distribution |
AL; AR; AZ; CA; CO; CT; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; NE; NH; NJ; NM; NV; NY; OH; OR; PA; RI; SC; TN; TX; UT; VA; VT; WA; WI; WV; WY; PR; ON; QC; Virgin Islands
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Discussion | Of the five subspecies of Zea mays, only the domesticated subspecies, Z. mays subsp. mays, is widely grown outside of research programs. Three wild subspecies are treated here, albeit briefly, because of their importance as genetic resources for Z. mays subsp. mays. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Zea mays subsp. parviglumis, which has the smallest fruitcases of all the wild taxa, is endemic to the Pacific slope of southern Mexico, from Oaxaca to Jalisco, being most abundant in the Balsas River drainage. It grows in highly seasonal, sunny thorn scrub, and open tropical deciduous forests and savannahs, at elevations of (450)600-1400(1950) m. One of its higher elevation populations appears to be the ancestor of subsp. mays. In the southern United States, Z. mays subsp. parviglumis is grown as part of breeding programs. In its native habitat, it tends to be seasonally isolated from subsp. mays, flowering a few weeks later, but the two sometimes form abundant hybrids in local areas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 701. | FNA vol. 25, p. 703. | ||||||||||||
Parent taxa | Poaceae > subfam. Panicoideae > tribe Andropogoneae > Zea | Poaceae > subfam. Panicoideae > tribe Andropogoneae > Zea > Zea mays | ||||||||||||
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Subordinate taxa | ||||||||||||||
Name authority | L. | H.H. litis & Doebley | ||||||||||||
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