Classification of the Euphorbiaceae

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Missouri Botanical Garden Press is collaborating with JSTOR to digitize, preserve and extend access to Annals of the Missouri Botanical Garden. ABSTRACTThe family Euphorbiaceae appears to be monophyletic, despite proposals for segregate families. The Euphorbiaceae display a great variety of growth forms, including at least 17 "models" of Hallk. Anatomical characters particularly useful for classification include wood structure, laticifer type, trichomes, and stomata. Inflorescences are basically dichasial, and pseudanthia have evolved several times. Pollen nuclear number and exine structure provide useful criteria for characterizing genera, tribes, and subfamilies. Structure of the seed coat is characteristic for the family and does not provide evidence for a polyphyletic origin of the family. Pollination is prevailingly entomophilous, and seed dispersal by ants is important in many taxa. Geographic distribution patterns of genera show a concentration of primitive taxa in Africa and Madagascar, although in subfamily Crotonoideae there is evidence of a neotropical center. Disjunctions between Africa and South America are common. Bentham's hypothesis of an Old World origin of the family appears well supported. The basic distribution patterns appear to reflect early (Cretaceous and Paleogene) dispersal across land or narrow water barriers and spectacular but rather trivial instances of long-distance dispersal in the late Tertiary and Pleistocene; Tertiary high-latitude dispersals via the Bering land bridge appear to have been relatively insignificant.The Euphorbiaceae, although one of the largest dicot families and conspicuous throughout the tropics, have been relatively neglected by systematists in the 20th century. While other families such as Compositae, Leguminosae, and Solanaceae have been the subjects of various symposia, the very first international conference with a major focus on Euphorbiaceae was held at Kew in 1986(Jury et al., 1987. The Kew symposium, on the Euphorbiales, was heavily biochemical in orientation and focused to a considerable extent on relationships between the Euphorbiaceae and other families. The present symposium in St. Louis is the first in which the classification of the family and its constituent infrafamilial taxa is the major focus of attention.The history of classification systems for the Euphorbiaceae at the subfamilial and tribal level has been reviewed in the Kew symposium on Euphorbiales (Webster, 1987). In my opinion, the two major milestones in this history were the classifications of Adrien Jussieu (1824), who identified the major series of genera that (after much later revision) correspond roughly to current subfamilies, and Jean Mueller (1...

A família Euphorbiaceae nas caatingas arenosas do médio rio São Francisco, BA, Brasil

“…É representado por cerca de 800 espécies, a maioria americana, embora tenham sido registradas mais de 200 espécies paleotropicais (Webster 1994b …”

“…O gênero Jatropha possui cerca de 150 espécies, em sua maioria africana e americana (Webster 1994b Jatropha mollissima distingue-se das demais espécies de Jatropha da área por suas lâmina foliar 5-lobada. É comum no nordeste do Brasil e norte da Argentina, sendo, segundo Pax (1910), nativa da caatinga e outras regiões secas do nordeste do Brasil e Minas Gerais.…”

“…Estes estão agrupados em 49 tribos e cinco subfamílias, segundo o sistema de classificação proposto por Webster (1994b).…”

Biologia reprodutiva de duas espécies de Jatropha L. (Euphorbiaceae) em caatinga, Nordeste do Brasil

“…O gênero Jatropha L. é constituído por 175 espécies tropicais e subtropicais (Webster 1994), monóicas, dióicas ou raramente poligâmicas (Gallindo 1985). Estudos de polinização no gênero são raros (Dehgan & Webster 1979, Reddi & Reddi 1983, Ormond et al 1984, Epila-Otara 1993, fato já apontado por Dehgan & Webster (1979) e Ormond et al (1984).…”

Pericarp ontogeny and histochemistry of the exotesta and pseudocaruncle of Euphorbia milii (Euphorbiaceae)

“…Euphorbiaceae is known by its explosively dehiscent dry fruits, described as schizocarps with three elastically dehiscent mericarps (cocci) and persistent columella (Webster 1994). While this type of fruit is prevalent in Euphorbiaceae, fleshy and indehiscent fruits are also found in the different subfamilies (Webster 1994;Esser 2003).…”