Monday, August 03, 2009

Gossypium thurberi

Gossypium thurberi | Desert cotton, Wild Cotton, Thurber's Cotton, Algodoncillo
Though closely related, Desert Cotton and cultivated cotton do not look alike. Cultivated cotton has large, yellow flowers, while Desert Cotton has smaller white ones. The major difference is found in the seeds. Those of cultivated cotton are enveloped in cotton fiber, while Desert Cotton seeds have only few scraggly hairs. Desert Cotton lives for several years and can become a woody plant.

Sometimes, instead of seeds, the small woody capsules contain the grubs of a certain cotton boll weevil. Although this particular weevil generally feeds only on wild cottons, it sometimes spreads to cultivated plants, and at one time the U. S. Department of Agriculture tried to eradicate desert cotton wherever it grew near cotton fields.

The cup-shaped flowers appear in the summer. Often there is a faint crimson spot at the base of each petal. Desert cotton grows on canyon slopes at the upper margin of the desert and the lower margin of oak woodland from southern Arizona into northern Mexico.

Historical Reference: The Thurberia, or so-called wild cotton (Thurberia thespesioides), is a malvaceous plant belonging in the same family as the cotton. It is a perennial shrub with a light grayish bark and attains a height of upwards of ten or more feet in older plants and a trunk of four or more inches in diameter. The leaves are rather small and palmate. The flowers are white and conspicuous and are borne terminally. These give space to the small bolls about one-half inch long which are generally divided into three capsules though four divisions are sometimes noted. Each capsule normally contains four small blackish seeds resembling in shape and color somewhat those of the common morning-glory. As the bolls ripen they burst, allowing the seeds to be scattered. These bolls, on casual observation, seem practically devoid of any lint, though there appears in the boll a small amount which can be seen with a glass.

The plant ordinarily blooms during the humid mid-summer raius, thus with the ripening and bursting of the bolls the seeds are picked up and deposited anywhere along the line of flow, being carried long or short distances according to the extent of the flood. As often happens in seasons of heavy rainfall, seeds are carried far down the wash, in fact some are carried down so far that with the following dry season, either by insufficient moisture to sustain them, or to the low relative humidity, they lead a precarious existence and finally perish.

   Bulletin - State of California, Department of Agriculture, California.
   State Commission of Horticulture
   Published by Dept. of Agriculture, 1921