Jatropha stevensii G.L.Webster

  • Authority

    Dehgan, Bijan. 2012. . Fl. Neotrop. Monogr. 110: 1--274. (Published by NYBG Press)

  • Family

    Euphorbiaceae

  • Scientific Name

    Jatropha stevensii G.L.Webster

  • Type

    Type. Nicaragua. Dept. Boaco, 1.6 km SW of Santa Cruz, W of Teustepe, 140-160 m, 12°24' N, 85°50' W, 7 Jun 1984 ([female], [male], fr, seed), W. D. Stevens 22902 (holotype; MO; isotypes: DAV, GH, K, MO, NY, US).

  • Description

    Species Description - Shrubs, to 3 m tall, monoecious. Stems; terete, grayish or reddish brown, glabrous or hispidulous; short shoots present; latex clear in younger stems but cloudy in older. Leaves: deciduous, borne on nodes but sometimes clustered on short shoots; stipules obsolete, petioles 0.5-2.5 cm long and 0.3-0.5 mm in diam.; blades ovate, undivided, 2-4 x 1-3 cm, chartaceous, base cordate, margins ciliate, apex acuminate, venation palmate with 5 noticeably raised veins from base, sparingly tomentose to glabrous on both surfaces. Inflorescences: terminal, many-flowered cymes, often with a coflorescence, peduncles 1-1.2 cm, paracladia hispidulous; bracts oblong-lanceolate to oblanceolate, 4-5 x 1.2-1.3 mm, glabrous or tomentulose; pedicels 0.5-11 mm long. Staminate flowers: sepals lanceolate, 2.5-4.8 x 1.2-2 mm, distinct, margins entire, apex obtuse or subacute, variously glabrous or sparsely pubescent on both surfaces; corollas tubular-campanulate, pale green; petals 5.5-6 x 1.5-2 mm, coherent ca. 1/3 of length, oblong, glabrous abaxially but pubescent adaxially in lower half; disk glands nearly square in outline, 0.5-0.6 mm high; stamens 10, monadelphous-biseriate (5 + 5), outer filaments 1 mm long, mostly distinct, inner filaments 3-4 mm long, connate ca. ½ of length. Pistillate flowers: like staminate but sepals elliptic to lanceolate, 5.5-6.5 x 2.5-3.8 mm; petals 6.5-7 x 1.8-2.5 mm, coherent ca. 1/3 of length, hirsute adaxially; disk somewhat rounded; carpels 3, smooth, glabrous, sharply carinate; styles 3 mm long, connate ca. ½ of length. Capsules: ± spherical, 1.2-1.4 cm in diam, smooth, 3-lobed with a distinct ridge on each lobe, tardily dehiscent. Seeds: brownish, ellipsoidal, small 1-1.2 x 2.5-4 mm; caruncle prominent and deeply lobed.

  • Discussion

    As aptly noted by Webster (1987), discovery of Jatropha stevensii in Nicaragua brings to three the number of south Central American species along with J. poda-grica (Nicaragua to eastern Guatemala, and Mexico) and J. costaricensis (Costa Rica). These three species belong to two subgenera and two sections (subg. Jatropha sect. Peltatae and subg. Curcas sect. Platyphyllae). The Central American species “appear to represent a depauperate extension of the large assemblage of endemic species in southern Mexico.” (Webster, 1987). As noted in earlier sections of this treatment, the floristic break for Jatropha comes in Guatemala and not at the Isthmus of Tehuantepec, but there is a definite decline in species diversity east of the Isthmus.

    According to Webster (1987), there is clearly no ancient, Central American center for xeric Euphor-biaceae, such as Cnidoscolus, Jatropha, and Manihot. In Mesoamerican Jatropha, there have been “invasions” of one species of subgenus Jatropha from the south (J. podagrica) and two species of subgenus Curcas from the north (J. costaricensis and J. stevensii). Gentry (1982) considered xeric, Mesoamerican taxa of plants to be of southern origin. Although the large number of Mexican species are more recent and may have evolved in situ, the most northern species with a geophytic growth habit, J. macrorhiza and J. cathartica (section Peltatae) and J. purpurea (section Jatropha), are probably remnants of an earlier introduction from South America.

  • Distribution

    Endemic to vicinity of Santa Cruz, Dept. Boaco, and San Juanillo, Dept. Matagalpa, Nicaragua.

    Boaco Nicaragua Central America| Matagalpa Nicaragua Central America|