An Introduction to the Subgeneric Classification of « Euphorbia » L., With Stress on the South African and Malagasy Species. Iii

Croizat, Léon

doi:10.1080/00837792.1972.10669972

Cited by 21 publications

(9 citation statements)

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“…Where the corolla is absent, petaloid calyces may occur, as in Cnidoscolus and Manihot. Croizat (1943) suggested that the perianth of Cnidoscolus is corolline and that the calyx had been lost; however, the evidence from vascular traces in Manihot contradicts this idea (Venkata Rao & Ramalakshmi, 1968;Venkata Rao, 1971). In past systems of classification of the Euphorbiaceae, great stress has been placed on aestivation of the calyx (whether imbricate or valvate), a practice initiated by Mueller (1866).…”

Section: Inflorescences and Flowersmentioning

confidence: 91%

“…However, it seems appropriate here to outline some of the major geographic patterns of the five subfamilies and indicate some of the most striking disjunct or relict distributions. There do not appear to be any critically documented maps of suprageneric taxa in the literature, and since the discussion of Bentham there have been few analyses besides the study of the distribution of Jatropheae by Pax (1910), and (partially) of the Euphorbieae by Croizat (1972) and Leach (1976).…”

Section: Geographic Distributionmentioning

confidence: 97%

“…Trees and shrubs predominate, as one would expect of a primarily tropical family, but herbs have evolved independently in all five subfamilies. The greatest diversity of growth form is seen in the genera Phyllanthus (Webster, 1956) and Euphorbia (Croizat, 1972;Cremers, 1977), which show a wide range of adaptations to relatively mesic and xeric habitats, respectively.…”

Section: A Growth Formmentioning

confidence: 99%

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Classification of the Euphorbiaceae

Webster¹

1994

Annals of the Missouri Botanical Garden

252

165

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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...

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Section: Inflorescences and Flowersmentioning

confidence: 91%

Section: Geographic Distributionmentioning

confidence: 97%

Section: A Growth Formmentioning

confidence: 99%

See 1 more Smart Citation

Classification of the Euphorbiaceae

Webster¹

1994

Annals of the Missouri Botanical Garden

252

165

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“…This centre, also known as the Caledon Centre, has long been recognised as the most species-rich area in the Cape as well as southern Africa (Levyns 1954, Dahlgren 1963, Croizat 1965, Nordenstam 1969. The moss centre of diversity is also more or less congruent with the Southwest Biogeographical Region of Bradshaw et al (2015), which they found to contain the highest levels of endemism and richness in the CFR.…”

Section: Main Centres Of Moss Diversitymentioning

confidence: 99%

“…The Drakensberg Alpine Region (Killick 1994) is generally recognised (under different names) as one of the southern African centres of vascular plant diversity and endemism (Weimarck 1941;Croizat 1965;Nordenstam 1969;Davis et al 1994;Cowling & hilton-Taylor 1994Van Wyk & Smith 2001). however, the Afromontane forests below c.1800 m, which greatly contribute to the high number of mosses in the Drakensberg subcentre, are generally excluded from the Drakensberg Alpine Region.…”

Section: Drakensberg Subcentre Of Moss Diversitymentioning

confidence: 99%

<p><strong>Centres of moss diversity in southern Africa</strong></p>

Rooy

Phephu

2016

Bryophyte Diversity and Evolution

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Moss diversity in southern Africa is greatest in the Cape Fold Mountains of the southwestern Cape, and the Drakensberg mountains along the Great Escarpment of KwaZulu-Natal, Mpumalanga and Limpopo Provinces of South Africa. Five main, and five secondary centres of moss diversity are described, based on the number of moss species per half degree grid square in southern Africa (South Africa, Namibia, Botswana, Lesotho and Swaziland). The main centres are the Southwestern Cape, outeniqua, Amathole, KwaZulu-Natal and Mpumalanga Centres of Moss Diversity. The KwaZulu-Natal centre is divided into the Drakensberg and Midlands Subcentres of Moss Diversity and the Mpumalanga centre into the Wolkberg and Blyde Subcentres of Moss Diversity. The secondary centres are the Cederberg, Witteberge, Pondoland, Magaliesberg and Soutpansberg Centres of Moss Diversity. Although collecting bias is responsible for concentrations of species records in many areas, moss diversity is strongly influenced by habitat heterogeneity and mean annual rainfall. This is in agreement with existing hypotheses of a broad-scale correlation between environmental heterogeneity and climate on the one side, and vascular plant diversity and distributions on the other.

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