Gossypium arboreum

Gossypium arboreum, known as tree cotton, is a shrub native to India and Sri Lanka. Evidence shows it was grown as far back as the Indus Valley Civilisation to make cotton cloth. The plant was catalogued in Linnaeus's *Species Plantarum* in 1753, and the same specimen he used—now housed in the Linnean Herbarium at the Swedish Museum of Natural History—serves as the holotype.

This shrub typically reaches one to two meters tall. Its purple branches are finely hairy. At the base of each leaf are stipules, which are linear to lance-shaped and sometimes sickle-like. Leaves attach via a petiole 1.5 to 10 cm long. The leaf blades are ovate to round, with five to seven lobes that give them a maple-like look; the lobes are linear to lance-shaped and often have a small tooth in the sinus. Glands line the midrib or occasionally nearby veins. Young leaves have both star-shaped and simple hairs, but these are lost as the leaf ages.

Flowers grow on short stalks. An epicalyx—a ring of bracts resembling sepals—surrounds the flower; its large, ovate segments are toothed along the edges, sometimes only faintly, and are heart-shaped at the base with pointed tips. The true calyx is small, about 5 mm long, cup-shaped, with five subtle teeth. The corolla is pale yellow, sometimes with a purple center, or occasionally entirely purple, and measures 3 to 4 cm long. The staminal tube, bearing the anthers, is 1.5 to 2 cm long. The fruit is a three- or four-chambered capsule, 1.5 to 2.5 cm across, ovoid or oblong, hairless, with a pitted surface and a beak at the tip. Inside, the seeds are round and wrapped in long white cotton.

A variant called "phuti karpas" was used to produce Dhaka muslin in Bengal (now Bangladesh). This type could only be grown south of Dhaka, along the Meghna River. Its fibers could be spun into threads that kept their strength at counts higher than any other cotton variant.