Monographs Details: Ionoxalis martiana (Zucc.) Small
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - Propagating plentifully through small, coated bulbs, and locally becoming a troublesome weed, this low, herbaceous plant, with attractive violet or rose-purple flowers is frequent in waste and cultivated grounds in Porto Rico, widely distributed in the West Indies, ranging north to Florida and to Bermuda. It is a native of South America, and has also been introduced into tropical parts of the Old World. The minits of its natural distribution are not now determinable. Ionoxalis (purple Oxalis) segregated as a genus by Small in 1903, contains over 100 species of perennial herbs, all American. They differ from the true Oxalis species in having the leaves all basal, tufted, arising from coated bulbs, as also the stalks of the clustered flowers which are not yellow, but mostly violet, purple, or white; Oxalis species have leaf-bearing stems, arising from rootstocks, and their flowers are mostly yellow. In Ionoxalis the leaves are long-stalked, compound, the leaflets 3, or more in some species. The clustered flowers are also mostly borne on a long stalk; there are 5, separate sepals, each with a pair of tubercles at the apex, and there are 5 petals; the 10 stamens are united at the base; the ovary is elongated, 5-celled and 5-lobed, and the styles are separate from each other. The fruit is a slender capsule. Ionoxalis Martiana (in honor of Karl Friedrich Philipp von Martius), is hairy, the stalks of the flower-clusters from 15 to 30 centimeters high, the leaf-stalks usually somewhat shorter; there are 3, nearly orbicular, thin leaflets from 2 to nearly 6 centimeters broad. The flowers are several or many in compound clusters, and borne on very slender stalks from 1 to 3 centimeters long; the sepals are from 4.5 to 6 millimeters long, the petals from 11 to 15 millimeters long. The fruit of this plant has not been described; we have studied many specimens, but have seen no capsules. Another species, Ionoxalis intermedia, differs by the leaflets being inversely deltoid and 2-lobed, and the flower-cluster is simple. It is occasional in Porto Rico, and also inhabits southern Florida, the Bahamas, Cuba, St. Croix, Guadeloupe and Martinique.

Discussion:Vinagrillo morado Purple Wood-sorrel Wood-sorrel Family Oxalis Martiana Zuccarini, Denkschriften der Akademie der Wissenschaften zu München 9: 144. 1825. Ionoxalis Martiana Small, Flora of the Southeastern United States 665.1903.