Zea mays

Zea mays, corn or maize, is a annual grass in the Poaceae (grass family) that originated in Central America and is one of the top three cereal crops grown in the world, along with rice (Oryza sativa) and wheat (Triticum spp.), with 2010 global commercial production of dried corn totaling 844.4 million metric tons, harvested from 161.9 million hectares.

Corn was domesticated in Mexico and Central America more than 7,000 years ago from teosinthe or wild maize (Z. mays subsp. mexicana). The corn plant may grow 1–4 m (3 to 13 ft) tall, with leaf blades 50 to 90 cm (19 to 35 in) long. The monoecious plant forms a terminal raceme (branched inflorescence) of male flowers—the tassel”--,while the axillary female inflorescences form cylindrical "cobs," each with 16–30 rows of spikelets (which develop into “kernels” when the seeds mature) and long protruding styles (the corn silks). Mature kernels are typically white or yellow, but may also range in color from red to purple.

Corn is used fresh (“green”) for human consumption, or may be dried and ground into flour or meal, important in Central American dishes, or popped and eaten as a snack. Corn oil, obtained from the grain, is used in cooking as well as many industrial uses, and cornstarch from processed grain is used as a thickener in sauces and puddings. Cornstarch can be further processed enzymatically to make high-fructose corn syrup, which has become widely used to replace sugar (sucrose) as an inexpensive sweetener in processed food and beverage products. In recent years, this use has become controversial, with critics charging that the sweetener is linked to obesity, but the American Medical Association has reported that additional research is needed to assess these claims.

In addition to use as a human food, the seed head and whole plant are used forage and silage, an important source of feed for livestock. Corn has become an increasingly important biofuel, both in the form of corn oil (used as bio-diesel) and ethanol (an alcohol fermented and distilled from the processed kernels), which is blended with petroleum-based gasoline in various proportions for use as fuel.

With Although grown in temperate and tropical countries worldwide, the U.S. alone produces more than one third of the global total of dried corn (316.2 metric tons), with China, Brazil, Mexico, and Argentina also producing significant amounts. Corn production increased by 42% worldwide over the past decade, associated with the increased demand and prices for corn as biofuel.

(AMA 2008, FAOSTAT 2012, Flora of China 2012, van Wyk 2005, Wikipedia 2012.)

Nile Valley North of Nubia, Nubia. 

Originally from central America, now cultivated throughout the tropics and subtropics, also grown for fodder in temperate regions.

Zea mays subsp. huehuetenangensis (Iltis & Doebley) Doebley:
Guatemala (Mesoamerica)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Zea mays var. huehuetenangensis Iltis & Doebley:
Guatemala (Mesoamerica)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Zea mays var. parviglumis Iltis & Doebley:
Guatemala (Mesoamerica)
Mexico (Mesoamerica)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Zea mays subsp. parviglumis Iltis & Doebley:
Guatemala (Mesoamerica)
Mexico (Mesoamerica)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Zea mays L.:
Argentina (South America)
Australia (Oceania)
Belize (Mesoamerica)
Burma (Asia)
Bolivia (South America)
Brazil (South America)
Canada (North America)
Chile (South America)
China (Asia)
Colombia (South America)
Costa Rica (Mesoamerica)
Ecuador (South America)
El Salvador (Mesoamerica)
Ethiopia (Africa & Madagascar)
French Guiana (South America)
Gabon (Africa & Madagascar)
Guatemala (Mesoamerica)
Guyana (South America)
Honduras (Mesoamerica)
Mexico (Mesoamerica)
Caribbean (Caribbean)
United States (North America)
Peru (South America)
Panama (Mesoamerica)
Nicaragua (Mesoamerica)
Suriname (South America)
Uruguay (South America)
India (Asia)
Venezuela (South America)
Paraguay (South America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

A native of America but now cultivated in all warm countries throughout the world.

Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

America, widely cultivated in all warm countries.

Annuals, Terrestrial, not aquatic, Prop roots present, Stems nodes swollen or brittle, Stems erect or ascending, Stems solitary, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes solid or spongy, Stems with inflorescence less than 1 m tall, Stems with inflorescence 1-2 m tall, Stems with inflorescence 2-6 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath and blade differentiated, Leaf sheath enlarged, inflated or distended, Leaf blades linear, Leaf blade auriculate, Leaf blades 2 or more cm wide, Leaf blades mostly flat, Leaf blade with prominen tly raised or widened midvein, Leaf blades mostly glabrous, Leaf blades more or less hairy, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule a fringed, ciliate, or lobed membrane, Inflorescence terminal, Inflorescence lateral or axillary, Inflorescence a dense slender spike-like panicle or raceme, branches contracted, Inflorescence with 2 or more spikes, fascicles, glomerules, heads, or clusters per culm, Inflorescence spike linear or cylindric, several times longer than wide, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence single raceme, fascicle or spike, Inflorescence with 2-10 branches, Inflorescence branches paired or digitate at a single node, Rachis enlarged, corky, Flowers unisexual, Plants monoecious, Spikelets sessile or subsessile, Spikelets laterally compressed, Inflorescence or spikelets partially hidden in leaf sheaths, subtended by spatheole, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets with 2 florets, Spikelets paired at rachis nodes, Spikelets in paired units, 1 sessile, 1 pedicellate, Pedicellate spikelet rudimentary or absent, usually sterile, Spikelets unisexual, Spikelets not disarticulating, or tardy, Spikelets closely appressed or embedded in concave portions of axis, Monoecious - staminate and pistillate spikelets on separate inflorescences, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes equal to or longer than adjacent lemma, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma 1 nerved, Lemma 3 nerved, Lemma glabrous, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea longer than lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis.

Culms erect, 1–4 m tall. Leaf sheaths with transverse veinlets; leaf blades 50–90 × 3–12 cm, glabrous or with tubercle-based hairs, margins scabrid, midvein stout; ligule ca. 2 mm. Female inflorescence a cylindrical "cob," with 16–30 rows of spikelets; glumes equal, veinless, margins ciliate; florets hyaline. Male inflorescence a "tassel" of many digitate racemes; spikelets 9–14 mm, unequally pedicellate, one pedicel 1–2 mm, the other 2–4 mm; glumes subequal, membranous, lower ca. 10-veined, margins ciliate, upper 7-veined; lower lemma and palea hyaline, subequal; upper lemma smaller than lower. Anthers orange, ca. 5 mm. Fl. and fr. summer–autumn. 2n = 20, 40, 80.

Annual; culm solid. Spikelets unisexual. Staminate spikelets in pairs, about 9 mm long; lower glume lanceolate, pubescent, keeled, long-ciliate, margin thinner, 9-11-nerved, as Iong as the spikelet; upper glume oblong-lanceolate, 7- nerved, nearly as long as the lower; lower lemma minutely hairy on the back and margins, 3-nerved, about 8 mm long; palea as long as the lemma; upper lemma smaller than the lower palea, cleft usually to the base; anthers 3, about 6 mm long. Pistillate inflorescence axillary, the spikelets in many rows on a thickened, almost woody axis, enclosed by numerous large foliaceous bracts or spathes, the tyles extremely long, like silky threads. Caryopsis greatly exceeding the glumes at maturity.

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Cultivated cereal (Maize, Corn).

Widely cultivated in China [originating in America; widely cultivated elsewhere].

Zea mays (Corn) introduced
(honeybees collect pollen & are non-pollinating; corn is wind-pollinated; this observation is from Robertson)

Bees (long-tongued)
Apidae (Apinae): Apis mellifera cp np

Foodplant / spot causer
immersed pycnidium of Ascochyta coelomycetous anamorph of Ascochyta straminea causes spots on live leaf of Zea mays

In Great Britain and/or Ireland:
Foodplant / saprobe
Chytriomyces nodulatus is saprobic on submerged leaf of Zea mays
Remarks: captive: in captivity, culture, or experimentally induced

Foodplant / feeds on
adult of Diabrotica virgifera virgifera feeds on live leaf of Zea mays

Foodplant / saprobe
internal Diplophlyctis intestina is saprobic on stem of Zea mays
Remarks: captive: in captivity, culture, or experimentally induced

Foodplant / saprobe
Entophlyctis aurea is saprobic on submerged leaf of Zea mays

Foodplant / saprobe
Alternaria dematiaceous anamorph of Lewia infectoria is saprobic on dead, fungus infected leaf of Zea mays

Foodplant / open feeder
caterpillar of Mamestra brassicae grazes on live leaf of Zea mays

Foodplant / miner
larva of Oscinella frit mines live leaf of Zea mays

Foodplant / miner
caterpillar of Ostrinia nubilalis mines live stem of Zea mays
Other: minor host/prey

Foodplant / feeds on
adult of Oulema melanopus/rufocyanea agg. feeds on leaf of Zea mays
Remarks: season: 1-12

Foodplant / parasite
black, open telium of Puccinia sorghi parasitises live sheath of Zea mays

Foodplant / pathogen
erumpent sorus of Ustilago maydis infects and damages live stem of Zea mays
Other: sole host/prey

Foodplant / saprobe
Volutella anamorph of Volutella colletotrichoides is saprobic on Zea mays

Annual.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 3
Specimens with Barcodes: 5
Species With Barcodes: 1

Canada

Rounded National Status Rank: NNA - Not Applicable

United States

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: GNR - Not Yet Ranked

These species are introduced in Switzerland.