Euphorbia L. Herbs to shrubs or succulents, small trees, prostrate or decumbent, all produce a mostly white latex which they exude when cut, and this sap is often toxic, characterized by the unique pseudanthium of much-reduced flowers (cyathium); recently all cyathia-bearing species were united into one single genus; thus, this feature is present in every species of the genus but nowhere else in the Plant Kingdom. 2,046 spp. (5th largest worldwide), fully cosmopolitan; succulent spurges are most diverse in southern and E Africa and Madagascar, but they also occur in tropical Asia and the Americas; 491 in New World, 246 spp. in Mexico (129 endemics), 182 in South America, 68 in Brazil (40 endemics). 4 subgenera and 64 section, three subgenera in New World (59 section joined) and South America (12 sections within).
The most morphological diverse genus of angiosperms in Brazil, and the 6ª largest group of succulent species worldwide, with c. 650 spp. E. laevigata Lam. (endemic to Brazil) unplaced. 64 lineages.
▪ sect. Anthacanthae ‣ 87 spp. found in southern Africa to very sparsely distributed over the rest of sub-Saharan Africa; bare, dry, stony plains with little other vegetation to deep Kalahari sand among scattered clumps of grass and trees to among fynbos vegetation, from sea level to 2700 m.
▪ sect. Antso ‣ only one sp., E. antso Denis., from W and SW Madagascar (Toliara Region), in semiarid, deciduous forests and scrub, often on soils derived from limestone, from sea level to 500 m.
▪ sect. Balsamis ‣ 9 spp., S Arabian Peninsula up into Iran, also to Sudan (Red Sea Hills), Somalia, Socotran Archipelago (Abd al Kuri only), as well as in West Africa and the Canary Islands, on dry stony slopes or stony flat plains and they sometimes form the dominant component of the otherwise very scanty vegetation.
▪ sect. Crotonoides ‣ 8 spp., S to E Africa, in Angola, Botswana, Namibia, South Africa, Zimbabwe, Malawi, Zambia, Tanzania, Kenya, Sudan and Ethiopia; on grassy hillsides, in leaf-litter under trees in dry open woodlands, on sand or loam, sometimes in disturbed patches, 200–3000 m.
▪ sect. Lyciopsis ‣ 19 spp., WC to E and NE Africa and the Arabian Peninsula (Oman, Saudi Arabia, Yemen, Socotra), extending into Angola, Botswana and Namibia; dry stony areas among deciduous shrubs and trees, gypsum, limestones, granites, or sand dunes, from sea level to 2100 m.
▪ sect. Pseudacalypha ‣ 11 spp., Ethiopia, Somalia, Sudan and the southern Arabian Peninsula (Oman, Yemen), extending to Angola, Egypt, Kenya and Tanzania; the non-succulent species occur in open, disturbed habitats, rocky terrain, sheltered among stones or under small shrubs; from sea level to 1800 m.
▪ sect. Somalica ‣ 13 spp., Tanzania, Kenya, Ethiopia, Somalia and Yemen (Socotra); dry, largely deciduous bushland in open flats, on slopes of rocky hills and escarpments, from near sea level to 1000 m.
IN NEW WORLD: this subgenus does not occur in New World, being largelly centered in Africa.
▪ sect. Biumbellatae ‣ 3 spp., endemic to the W Mediterranean region (Spain, France, Italy, Algeria, Morocco, Tunisia).
▪ sect. Aphyllis ‣ 23 spp., Macaronesian islands (except for the Azores), southern coast of Portugal, and the Atlantic coast of Morocco and Western Sahara, Africa, S Arabian Peninsula, Socotra, and Madagascar.
▪ sect. Arvales ‣ 7 spp., Mediterranean region and neighboring areas, Canary Islands, Iranian highlands, central Asia to N Afghanistan, W China, and India; on open stony or gravelly slopes, in steppes and deserts, in fields and by roadsides.▪ sect. Calyptratae ‣ two spp., deserts and steppes of N Africa (E. calyptrata Coss. & Durieu) and Iran (E. connata Boiss.).▪ sect. Chylogala ‣ 4 spp., Mediterranean region, Arabian Peninsula, SW and C Asia (to N PamirAlay and W Tien-shan); in deserts and steppes, on stony mountain slopes and by dry streams, or in fallow fields.▪ sect. Esula ‣ 96 spp., widespread in Europe and Asia, also in Africa, Madagascar, Réunion, Indonesia (Java), New Zealand, and Samoa, introduced in the New World and elsewhere; in meadows (lowland to montane), steppes, semideserts, riparian and littoral vegetation, sometimes in forests, weedy in arable lands, along roads and other disturbed areas.▪ sect. Exiguae ‣ 5 spp., S Europe, northern Africa, Asia, Macaronesia, Mauritius, the Comoros, and Madagascar; in grasslands, rocky or sandy subdeserts, rock fissures in mountains, weedy areas, abandoned cultivated areas, from sea level to 2200 m.▪ sect. Guyonianae ‣ only one sp., E. guyoniana Boiss. & Reut., from NW Africa (Morocco to Libya); dunes and sandy areas on the northern edge of the Saharan Desert.▪ sect. Helioscopia ‣ 136 spp., most diverse across Eurasia and North Africa, but a few species also present in eastern Africa, Macaronesia, and the New World (26 spp.); the range of habitats is very diverse, from montane forests to steppes, rocky outcrops and wetlands, with a few weedy species; most species are associated with mountains and are fairly mesic, although some are widely distributed in lowland areas. 2 spp. in South America, E. philippiana (Klotzsch & Garcke) Boiss., widely disjunct to central Chile and is the only species in subg. Esula endemic to South America, and one in Brazil, E. spathulata Lam. disjunct from Canada to Mexico, and southern Brazil, NE Argentina and Uruguay.
▪ sect. Herpetorrhizae ‣ 12 spp., Asia, from Turkey and Caucasus to Kuwait, Pakistan, and Afghanistan, and into W China; on sand, clay and saline soils in deserts and steppes, and on stony slopes of mountains.
▪ sect. Holophyllum ‣ 27 spp., mountainous areas of E and C Asia, the Himalayas, S Siberia, NE China, Korea, and Japan, with one species disjunct in the Iberian Peninsula; in forests, steppes, on rock outcrops, and in alpine meadows.
▪ sect. Lagascae ‣ 3 spp., Canary Islands, Mediterranean region, and western part of Iranian highlands, in grasslands and ruderal habitats.
▪ sect. Lathyris ‣ only one sp., E. lathyris L., found mostly in cultivation or near human settlements, in two main areas: eastern Asia and the Mediterranean, but also widely distributed by humans and found in temperate or subtropical regions worldwide.▪ sect. Myrsiniteae ‣ 14 spp., Mediterranean region, Caucasus to the Iranian highlands, usually growing in dry, exposed, rocky habitats.▪ sect. Pachycladae ‣ two spp., Circum-Mediterranean region; both species are mainly littoral, but can penetrate up to 100 km inland, in summer-arid areas, on coastal sands in littoral scrub, on edges of roads and trails, on substrates of siliceous, schistose, gypseous, volcanic, or calcareous origin, from sea level to 800 m▪ sect. Paralias ‣ 12 spp., Mediterranean region, Balkans, Caucasus, Macaronesia (including Azores), with E. tricotoma Kutnh in S. Florida, SE. Mexico to Belize, Bahamas, Cuba, Cayman Islands; often in coastal sandy habitats but some species farther inland and upland.▪ sect. Patellares ‣ 14 spp., Mediterranean region and mountains of central Europe, the Balkan Peninsula, Caucasus, and Iranian highlands; in forests and montane meadows or rocky habitats.▪ sect. Pithyusa ‣ 50 spp., mainly Mediterranean and neighboring areas, Iranian highlands and montane regions of central Asia, with a few species in the steppe zone of Eurasia and in the mountains of eastern Asia (at least as far east as Thailand); on rocky (calcareous) substrates, in steppes and steppe-like grasslands, deserts, dry scrub, and gypsum hills, sometimes weedy.▪ sect. Sclerocyathium ‣ 9 spp., SW and central Asia, including the Himalayas; on dry stony mountain slopes, sometimes in steppes.▪ sect. Szovitsiae ‣ only one sp., E. szovitsii Fisch. & C.A. Mey., from Caucasus, Turkey, Iranian highlands, southern part of central Asia; on gravel slopes, screes, stream beds, or in steppes.
▪ sect. Tithymalus ‣ 35 spp., 7 native to and restricted to the Old World from the eastern Mediterranean region to Iran and the Arabian Peninsula; E. peplus L. is also presumably native to the Mediterranean region but is now widespread worldwide; the remaining species are native to the New World from United States, Canada, Mexico, Central America, Hispaniola. Many of them are restricted to relatively high montane habitats, but others occur at lower elevations and are either widespread or local.
C. subg. Chamaescyce (SEE) ‣ 566-574 spp. worldwide, 15 sections, 4 in South America; subg. Chamaescyce is the only taxonomic group at the lower level than the genus with photosynthesis C3, C2, C4 and CAM, with C2 in this group occurring only in E. acuta Engelm. (U.S.A.) and E. johnstoni Mayfield (Mexico).
▪ sect. Bosseriae ‣ 3 spp., SW and S Madagascar, in xerophytic vegetation, ca. 50–500 m.
▪ sect. Alectoroctonum ‣ 115 spp., widespread in the New World from Canada to Argentina, with a center of diversity in Mexico and Central America; tropical and subtropical forests, desert scrub, and disturbed areas, sea level to 3000 m.
▪ sect. Anisophyllum ‣ two subsections.
o subsect. Acutae ‣ two spp., W Texas and Mexico (Coahuila, Durango, Tamaulipas); grassland to desert scrub in and around the Chihuahuan Desert on sandy or gravelly limestone substrates, 200–1500 m.
o subsect. Hypericifoliae ‣ 365 spp., warm, arid and semi-arid vegetation or disturbed habitats, and summer annuals in temperate areas; worldwide, from sea level to 4000 m; 30 spp. in Brazil, 11 endemics.
▪ sect. Articulofruticosae ‣ 18-26 spp., most diverse in the arid winterrainfall region of W South Africa and S Namibia, extending into southern Angola and Botswana and east to KwaZulu-Natal, South Africa; growing in sandy soils or on rock outcrops, in low shrublands to deserts and consolidated dunes, from sea level to ca. 2000 m.
▪ sect. Cheirolepidium ‣ two spp., from N Africa through Central Asia; fallow fields and dry, open habitats, 500–1500 m.▪ sect. Crossadenia ‣ two sections.
o subsect. Apparicianae ‣ 4 spp., E. flaviana Carn.-Torres & Cordeiro; E. sobolifera O.L.M. Silva & P.J.Braun; E. appariciana Rizz. and E. teres M. Machado & Hofacker, all endemics to Bahia state, Brazil, growing on granitic domes (inselbergs) or sandstone outcrops, 250–1200 m.
o subsect. Ephedropepplus ‣ 8 spp., 7 endemics to NE Brazil in Tocantins, Bahia, Goiás, Minas Gerais, Distrito Federal, Pernambuco and Piauí states, in rocky grasslands vegetation on sandy substrates and Atlantic sandy coastal shrublands (restingas), sea level to 1400 m, and E. riinae V.W.Steinm. endemic to Bolivia; E. gymnoclada Boiss. is the only aphyllous in this group.
▪ sect. Denisiae ‣ two spp., southern Madagascar, in xerophytic vegetation, sea level to 200 m.▪ sect. Eremophyton ‣ 3 spp., Australia, New Caledonia, Vanuatu; coastal sands to inland desert and scrub, sea level to 600 m.▪ sect. Espinosae ‣ 2 spp., S and E Africa (Angola, Botswana, Namibia, N South Africa, Kenya, Malawi, Tanzania, Zambia, Zimbabwe); hilly, deciduous woodlands, 300–1400 m.▪ sect. Frondosae ‣ 7 spp., E to southern Africa (Angola, Botswana, Ethiopia, Kenya, Malawi, Mozambique, Namibia, South Africa, Tanzania, Uganda, Zambia, Zimbabwe) and Arabian Peninsula (Oman, Saudi Arabia, Yemen); open to dense bushland, forest, 400–2700 m.▪ sect. Gueinziae ‣ only E. gueinzii Boiss., South Africa (Mpumalanga, Free State, KwaZulu-Natal, E Cape), Lesotho, and Swaziland; grasslands on rocky slopes and above sandstone cliffs, 200–2000 m.▪ sect. Plagianthae ‣ 2 spp., southern Madagascar, in xerophytic and semi-xerophytic vegetation; sea level to 1000 m.▪ sect. Poinsettia ‣ 4 subsections.
o subsect. Lacerae ‣ two spp., W & C Mexico; xerophytic scrub, wooded ravines, 900–2500 m.
o subsect. Erianthae ‣ only E. erianthe Benth., SE U.S.A. (Arizona, California, New Mexico, Texas) and northern Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Sonora); desert scrub and thorn scrub on rocky slopes and along washes, sea level to 900 m.
o subsect. Extipulatae ‣ 2 spp., SW U.S.A. to S Mexico; desert scrub, grasslands, oak forest, riparian areas.
o subsect. Stormieae ‣ 21 spp., widespread in the New World, from Canada to Argentina, but with a center of distribution in Mexico; in a wide variety of habitats from desert scrub to moist montane forests, sea level to 2700 m.
▪ sect. Scatorhizae ‣ 7 spp., Africa (Angola, Ethiopia, Kenya, Somalia, Tanzania), Arabia (Saudi Arabia, Yemen), India; rocky or sandy scrub or deserts, 200–1850 m.▪ sect. Tenellae ‣ 4 spp., Southern Africa (Angola, Botswana, Namibia, South Africa, Zimbabwe); in open desert areas, exposed gravelly or sandy soils and rocky slopes, ca. 100–1100 m.
D. subg. Euphorbia (SEE) ‣ 661 spp. worldwide, 21 sects., eight occur in South America.
▪ sect. Brasilienses ‣ 5 spp. from Espírito Santo, Bahia, Minas Gerais, Paraíba and Pernambuco, in rocky uplands (campos rupestres), grasslands, thorn scrub, and tropical deciduous forest.
▪ sect. Calyculatae ‣ two spp., Mexico (Jalisco, Michoacán, Guanajuato, Guerrero, Mexico, Oaxaca, Puebla); deciduous montane woodlands, oak and pine oak forest, sometimes on lava flows, 1600–2300 m.
▪ sect. Crepidaria ‣ 15 spp., Mexico (highest diversity), Central America, Caribbean, northern South America; in South America only one, E. tythymaloides L., over in tropical South America; desert scrub, as well as dry and wet tropical forests, sea level to ca. 800 m.▪ sect. Cubanthus ‣ 9 spp., Caribbean (Bahamas, Cuba, Jamaica); scrub forest mostly on limestone, sea level to 800 m (Amaro, 2017, SEE).
▪ sect. Denisophorbia ‣ 13 spp., Madagascar, Mayotte and Comoro Islands, Seychelles, Mauritius.
▪ sect. Deuterocalli ‣ 3 spp., widespread in Madagascar, mostly in dry scrub or among rocks in moister habitats, sea level to ca. 500 m.▪ sect. Euphorbia ‣ 244 spp., widespread across most of Africa, Arabian Peninsula, and in southern Asia from Pakistan to Malaysia, Indonesia and Papua New Guinea; in a wide variety of habitats, but especially in arid landscapes, open areas, dry forests, scrub, rock outcrops, with some species occurring in moist forests.
▪ sect. Euphorbiastrum ‣ 6 spp., Northern and central Andes of South America (Venezuela, Colombia, Ecuador, Peru), to southern Mexico and Caribbean (Windward Islands); montane scrub and forest edges, lowland moist forests.▪ sect. Goniostema ‣ 76 spp., widespread across the island of Madagascar; in a wide variety of habitats from sea level to upper mountains.
▪ sect. Lactifluae ‣ only E. lactiflua Phil., northern Chile, rocky areas of Atacama Desert from the region of Antofagasta south to the vicinity of Copiapó; nearly sea level to 700 m.▪ sect. Mesophyllae ‣ only E. sinclairiana Benth., from Mexico (Chiapas), to Colombia, Peru and Brazil (Acre); understory of wet, lowland forests but also extending to higher elevations in cloud forest, from near sea level to ca. 800 m.
▪ sect. Monadenium ‣ 90 spp., E, C, and SE tropical Africa; in a variety of mostly arid habitats: thickets, rock outcrops, and other open areas.
▪ sect. Nummulariopsis ‣ 37 spp., SE U.S.A., southern South America (Argentina, Bolivia, Brazil, Chile, Paraguay, Peru, Uruguay); high montane habitats, grasslands, and sand dunes (South America), pine woodlands and sandy areas (U.S.A.), sea level to ca. 3500 m; 10 spp. in Brazil, 7 endemics.▪ sect. Pachysanthae ‣ 4 spp., Madagascar; in a variety of habitats, such as thickets in xeric bush of the southeast, tsingy (karst) formations in the north, remnant forests in the high plateaus in the northwest, and rainforest relicts of the central east.▪ sect. Pervilleanae ‣ 7 spp., widespread across Madagascar.▪ sect. Pacificae ‣ 11 spp., Australia, Indonesia, New Guinea, Philippines, and Pacific Islands (Norfolk Island, Fiji, Solomon Islands, Hawaii); the Australian herbaceous or pencil-stemmed species occur in dry interior or coastal habitats, whereas the remaining species occur in tropical or subtropical moist forests or scrub.▪ sect. Portulacastrum ‣ two spp., Chile and Bolivia, montane habitats.
▪ sect. Rubellae ‣ 3 spp., NE Africa (Sudan, Ethiopia, Kenya, Uganda); open sites in limestone crevices on well-drained soil, or under bushes in evergreen or deciduous bushland.▪ sect. Stachydium ‣ 6 spp., northern South America to E Brazil; low deciduous forest and thorn scrub on sandy or loose stony soils or rocky outcrops; 200 - 1200 m; two spp. in Brazil, E. comosa Vell. in Brazil, Colombia and Venezuela and E. heterodoxa Mull. Arg. is endemic.▪ sect. Tanquahuete ‣ two spp., W & C to S Mexico; subtropical deciduous forests in montane canyons and lava flows; near sea level to 2100 m, species that are by far the tallest members of Euphorbia in the New World, and among the largest in the genus.
▪ sect. Tirucalli ‣ 25 spp., widespread and most diverse in Madagascar, also native in Arabian Peninsula (Oman and Yemen, including Socotra) and Africa (Angola, Namibia, Somalia, and South Africa). E. tirucalli L. is widespread across Africa, but it is not clear where the species is native (probably Madagascar and southern Africa). It is widely cultivated in India and in other tropical countries.
