Tribulus cistoides L.

• Title

  Tribulus cistoides L.

• Authors

  Nathaniel Lord Britton, Frances W. Horne

• Scientific Name

  Tribulus cistoides L.

• Description

  Flora Borinqueña Tribulus cistoides Abrojo West Indian Buttercup Family Zygophyllaceae Caltrop Family Tribulus cistoides Linnaeus, Species Plantarum 387. 1753. Banks along roads in the eastern part of San Juan have been turned golden-yellow in recent years, by the luxuriant growth and profuse flowering of this low, herbaceous plant, sometimes forming large patches; it is perennial by thick, woody roots. While its natural distribution is wide, extending from the southern United States, through most of the West Indies and continental tropical America, and it grows also in the Old World tropics, we think that it is not native in Porto Rico, being, apparently, restricted to the situations mentioned, seen once near Martin Peña, and recorded as formerly observed by Bello at Guanica. In growth and color the plant resembles some kinds of northern Buttercups, but there is no botanical affinity. Abrojo, the Spanish name used for it and its relatives is that of the ancient implement Caltrop, from the resemblance of its fruit, and Large Yellow Caltrop is another name. Tribulus (Greek, 3-pronged, Caltrop, from the spine-armed fruit), includes about 12 species of herbaceous plants, natives of warm and tropical regions, with stipulate, once-compound leaves of several pairs of leaflets, and axillary, stalked, yellow, regular and perfect flowers. The calyx has 5, persistent sepals, the corolla 5, broad petals; there are 10, separate stamens, the alternating ones somewhat the longer; the hairy ovary is 5-lobed, and 5-celled, with few or several ovules in each cavity, the style short, the stigma 5-ridged. The characteristic fruit is 5-angled, spiny, and splits, when ripe, into 5, few-seeded segments. Tribulus cistoides (like Cistus, an Old World genus of a quite different family), has procumbent, branched stems about a meter or shorter, hairy when young. The leaves are from 1 to 5 centimeters long, with from 6 to 8 pairs of obliquely oblong or elliptic leaflets from 4 to 15 millimeters long, and silky-hairy beneath; the very narrow stipules are from 5 to 8 millimeters long. The flowers are solitary, on stalks about as long as the leaves; the lance-shaped sepals are about 1 centimeter long, the petals about 2 centimeters long; each segment of the tubercled, hairy fruit has 2, stout, divergent spines, and, sometimes, smaller, scattered ones.