Kallstroemia maxima (L.) Hook. & Arn.

• Title

  Kallstroemia maxima (L.) Hook. & Arn.

• Authors

  Nathaniel Lord Britton, Frances W. Horne

• Scientific Name

  Kallstroemia maxima (L.) Hook. & Arn.

• Description

  Flora Borinqueña Kallstroemia maxima Abrojo Caltrop Family Zygophyllaceae Caltrop Family Tribulus maximus Linnaeus, Species Plantarum 386. 1753. Kallstroemia maxima Torrey and Gray, Flora North America 1: 213. 1838. A prostrate, annual herb, with once-compound leaves, and small, axillary, yellow flowers, frequent in fields, on banks and roadsides, sometimes a weed in cultivated grounds, at lower and middle altitudes in Porto Rico, most plentiful in dry districts, found also on the islands Vieques and Culebra. The species is distributed nearly throughout tropical and warm-temperate America, ranging northward to Georgia. Kallstroemia, a genus established by the Italian botanist Scopali in 1777, was named by him in honor of Kallstroem, but with no biographical record; the species here illustrated is typical. It is composed of about 20 species of herbs, mostly annuals, natives of warm and tropical regions, with opposite, stipulate, pinnately compound leaves, stalked yellow, stalked, solitary, axillary flowers. The calyx has 5 or 6, separate sepals, and there are from 4 to 6, obovate, or oblanceolate petals, which early fall away; there are twice as many stamens as petals, with versatile anthers. The ovary is from 8-celled to 12-celled, usually with only 1 ovule in each cell; the compound style is topped by a round stigma. The roughened, or tubercled, 6-angled to 12-angled, beaked fruit separates, when mature, into 8 to 12 nutlets. Kallstroemia maxima (large, but the term is relative) has slender, prostrate, hairy branches from 15 to 50 centimeters long. The short-stalked leaves have 3 or 4 pairs of oval or oblong, inequilateral, thin leaflets from 5 to 20 millimeters long, rounded, or somewhat heart-shaped at the base. The slender flower-stalks are from 1 to 4 centimeters long; the lance-shaped, hairy sepals are persistent, the light yellow, obovate petals, fading darker, from 7 to 8 millimeters long. The fruit is without hairs, 4 or 5 millimeters long, its beak about as long, the nutlets tubercled and cross-ridged. Another species, Kallstroemia caribaea, also of wide distribution, occurs in the southern dry parts of Porto Rico; its fruit hairy.