Monographs Details: Emelista tora (L.) Britton & Rose ex Britton & P.Wilson
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - A common, annual weed, distributed throughout nearly all tropical and warm-temperate regions, with rather conspicuous yellow flowers, and slender, long, curved pods, its original home unknown, but probably American. Linnaeus, and some subsequent authors, regarded the plants of tropical America and of tropical Asia as two different species, but that opinion has been found to be untenable. Coffee-weed and Low Senna are other English names; the Spanish name cited, meaning sleepiness, is the same as that used for the Opium Poppy (Papaver somniferum), but for quite different reason, this weed being "sleepy" by folding its leaflets at night. It ranges northward, in America, to Pennsylvania and Missouri, and is plentiful in waste and cultivated grounds in Porto Rico.
Emelista (derivation not explained) was founded as a genus by the naturalist Rafinesque in 1838, and includes a few species of annual herbs, the one here illustrated typical, and the only one growing in Porto Rico. They have once-compound leaves, with several pairs of broad leaflets, a slender gland borne between or above the lower pair. The flowers are borne several together, or solitary, in the leaf-axils, with 5, blunt, nerved sepals, 5, nearly equal, broad petals, 6 or 7 perfect stamens and usually 3 imperfect ones (staminodes); the slender ovary contains many ovules. The pod is long and slender, somewhat 4-sided, or nearly round, and splits longitudinally when ripe, releasing the many seeds.
Emelista Tora (aboriginal name in India) is smooth, or slightly hairy, about 1 meter high, or much lower. The leaves are from 8 to 15 centimeters long, with stalks from 1 to 4 centimeters long, and very narrow stipules lO to 15 millimeters long, which early fall away; they have from 2 to 4 pairs of thin, short-stalked, obovate, blunt, or minutely tipped leaflets from 1.5 to 5 centimeters long. The short-stalked flowers are few together, or solitary; the oblong sepals are from 5 to 8 millimeters long, the petals about twice as long. The usually strongly curved pods are from 10 to 20 centimeters long, from 3 to 5 millimeters wide, compressed-tetragonal, containing many, oblong, flattened, shining seeds about 5 millimeters long.
Cassia Tora Linnaeus, Species Plantarum 376. 1752.
Cassia obtusifolia Linnaeus, Species Plantarum 377. 1753.
Emelista Tora Britton and Rose; Britton and Wilson, Scientific Survey of Porto Rico and the Virgin Islands 5: 371. 1924.