Zea mays
Zea perennis
corn, cultivated corn
perennial teosinte
(0.5)1-3(6) m tall, (0.5)1-5 cm thick.
1-2.5 m tall, 1.5-2 cm thick, loosely clumped, usually branched above.
mostly 30-90 cm long, 2.5-12 cm wide.
20-65(80) cm long, 2-4.5 cm wide, linear.
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 by the lower glumes.
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.
peduncles 1-2(3) per node, 10-25 cm, at least 1 and sometimes 2 extending far beyond the terminal leaf sheaths; pistillate rames 4-8 cm long, 4-6 mm thick, distichous, with 5-10 solitary spikelets, distal portions often staminate;
fruitcases trapezoidal in side view, 6-9 mm on the long side, 2.5-4.5 mm on the short side, 4-5 mm in diameter.
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.
staminate panicles 12-20 cm, with 2-8 branches;
branches 9-15 cm, erect to nodding, internodes 2.4-6.2 mm;
spikelets 8.5-11 mm long, 2-2.5(3.2) mm wide, densely imbricate;
lower glumes flat dorsally, stiff, not translucent, margins tightly enclosing the upper glumes, lateral veins prominent, strongly winged distally.
= 20.
= 40.
Zea mays
Zea perennis
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 perennis is parapatric to Z. diploperennis, being native to the northern base of the Volcan de Colima, Jalisco, Mexico, at elevations of 1520-2200 m. It is rare, although locally abundant, in and around maize fields and orchards in former open oak and pine forests and savannahs. Zea perennis crosses infrequently with Z. mays subsp. mays. The hybrids, being triploid, are sterile. It has also been cultivated at research stations in the United States for many years and Hitchcock (1951) reported that it was established at James Island, South Carolina. It is not known if the population has persisted.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Pistillate inflorescences cylindrical spikes, 2-5(10) cm thick, with 8-24+ rows of spikelets pairs, each inflorescence tightly and permanently enclosed by several leaf sheaths and a large prophyll, not disarticulating at maturity; caryopses 60-1000+, not concealed by the glumes; staminate panicle branches not disarticulating below the sessile spikelets, lacking abscission layers; central axis of the staminate panicles polystichous, much thicker than the lateral branches; obligate domesticate | subsp. mays |
1. Pistillate inflorescences cylindrical, distichous rames, less than 1 cm thick, with 2 rows of spikelet pairs, each rame usually enclosed by a single leaf sheath and a prophyll, disarticulating at maturity into fruitcases; caryopses 4-15, each one concealed within a fruitcase; staminate panicles composed of rames that disarticulate below the sessile spikelets and have evident abscission layers; central axis of the staminate panicles similar in width to the rames; in the Flora region, wild taxa are known only from research plantings. | → 2 |
2. Staminate spikelets (6.6)7.5-10.5 mm long; fruitcases 6-10 mm long, 4-6 mm wide; staminate panicles with 1-35+ ascending to divergent, rather stiff branches | subsp. mexicana |
2. Staminate spikelets 4.6-7.2(7.9) mm long; fruitcases 5-8 mm long, 3-5 mm wide; staminate panicles usually with 10-100(235) divergent to nodding branches. | → 3 |
3. Leaves pubescent; staminate panicles with (2)10-100(235) branches | subsp. parviglumis |
3. Leaves glabrous or almost so; staminate panicles usually with fewer than 40 branches | subsp. huehuetenangensis |
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