Gossypium hirsutum L.

Upland Cotton


CC = *
CW = 5
MOC = 7

© SRTurner

Family - Malvaceae

Habit - Annual forb.

Stem - Ascending to erect, to 1.3 m, usually branched, pubescent with spreading, simple or fasciculate hairs.

Gossypium_hirsutum_stem.jpg Stem and nodes.

© SRTurner

Leaves - Alternate, long-petiolate. Blades 3-10 cm long, broadly ovate to nearly circular in outline, 3-or 5-lobed, the base cordate, the lobes broadly triangular, tapered to pointed tips, the margins entire, the surfaces pubescent with sparse to dense stellate hairs. Stipules tending to shrivel before flowering, 3-9 mm long, linear to elliptic-lanceolate.

Gossypium_hirsutum_leaf1.jpg Leaf adaxial.

© SRTurner

Gossypium_hirsutum_leaf2.jpg Leaf abaxial.

© SRTurner

Gossypium_hirsutum_leaf2a.jpg Leaf abaxial surface.

© SRTurner

Inflorescences - Flowers solitary or in small clusters in the leaf axils, the bractlets subtending the calyx 3, conspicuous and exceeding the calyx, 20-45 mm long, broadly ovate-cordate, overlapping, the margins incised with deep narrow lobes.

Flowers - Calyces 5-24 mm long, cup-shaped at fruiting, the sepals fused nearly to the tip, the lobes broadly triangular. Petals 25-55 mm long, the tips broadly rounded, the margin usually slightly irregular, white or more commonly pale yellow, sometimes pinkish- or purplish-tinged, often with minute dark glandular dots. Stamens numerous, the staminal column circular in cross-section, with a low crown of teeth at the tip, the anthers yellow. Pistils with 3-5 locules, the carpels closely fused. Style unbranched, with 3-5 linear longitudinal stigmatic areas toward the tip.

Gossypium_hirsutum_flower.jpg Flower.

© SRTurner

Gossypium_hirsutum_bractlets.jpg Bractlets.

© SRTurner

Gossypium_hirsutum_calyx.jpg Calyx, with bractlets peeled back.

© SRTurner

Gossypium_hirsutum_corolla.jpg Corolla.

© SRTurner

Gossypium_hirsutum_functional.jpg Staminal column.

© SRTurner

Fruits - Capsules, broadly ovoid to nearly globose, dehiscing longitudinally from the tip, glabrous. Seeds 5-11 per locule, 7-10 mm long, narrowly obovoid, the body hidden by a dense covering of shorter white matted hairs and long fluffy white fibrous hairs.

Gossypium_hirsutum_fruit1.jpg Immature fruit.

© SRTurner

Gossypium_hirsutum_fruits.jpg Dehiscent capsules ("bolls").

© SRTurner

Flowering - July - September.

Habitat - Roadsides, railroads, open disturbed areas. Widely cultivated and escaping sporadically.

Origin - Native to Mexico and the Caribbean.

Lookalikes - None.

Other info. - Cotton has been cultivated since antiquity. In Missouri it is grown in the Mississippi Lowlands region and adjacent Ozark counties. Escapes from cultivation are rare. The plant is recognized by its large, Malvaceae-patterned flowers having a distinct staminal column, and leaves with large, triangular lobes.

Mature, dehiscing capsules are known in the cotton trade as "bolls." The cotton fibers surround the seeds, and are of two types: long fibers, known as "staples," and shorter fibers, known as "linters." These fibers are separated from the seeds (and from each other) by the ginning process. Varieties of cotton exist which have naturally brown or green fibers. Although fibers are the main product of commercial interest from the plant, an edible oil useful in cooking can be also be expressed from the seeds.

Some 2.5% of the world's arable land is used for cotton production. The genus name is derived from the Arabic word "goz," which refers to a soft material.

Photographs taken along a roadside near Dexter, Stoddard County, MO, 11-2-2008, and near Holly Ridge Conservation Area, Stoddard County, MO, 8-15-2021 and 8-7-2022 (SRTurner).