A revised infrageneric classification and molecular phylogeny of New World Croton (Euphorbiaceae)

Croton (Euphorbiaceae) is a large and diverse group of plants that is most species‐rich in the tropics. We update the infrageneric classification of the New World species of Croton with new evidence from phylogenetic analyses of DNA sequence data from all three genomes. The relationships of species that were previously placed in conflicting positions by nuclear and chloroplast data, such as C. cupreatus, C. poecilanthus, and C. setiger, are further resolved by adding the nuclear EMB2765 and mitochondrial rps3 genes to the molecular sampling. Analyses of rps3 reveal an accelerated rate of evolution within Croton subg. Geiseleria, the only one of the four subgenera that contains numerous herbaceous, annual species. We provide morphological descriptions, species lists, and a key to the 31 sections and 10 subsections recognized in the New World. New taxa that we describe include C. sects. Alabamenses, Argyranthemi, Cordiifolii, Corinthii, Cupreati, Luetzelburgiorum, Nubigeni, Olivacei, Pachypodi, Prisci, and C. subsects. Cubenses, Jamaicenses, and Sellowiorum. Additional transfers are made to the ranks of subgenus, section, and subsection. A total of 712 species of Croton are currently recognized for the New World, with 702 of them assigned here to section.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146834/1/tax603013.pd

Dos nuevas especies suramericanas de Croton (Euphorbiaceae) y sus afinidades filogenéticas

Two rarely collected species of Croton from South America are des cribed and illustrated. Croton chimboracensis P.E. Berry & Riina is localized in western Andean Ecuador and is sister to Croton sect. Adenophyllum Griseb. Croton abonari Riina & P.E. Berry is known from a single location in Amazonian Brazil; it resembles both C. sampatik Müll. Arg. and members of Croton sect. Cuneati (G.L. Webster) Riina & P.E. Berry, but C. abonari can be easily distinguished from both groups by distinctive morphological charactersSe describen e ilustran dos especies raras de Croton de Suramérica. Croton chimboracensis P.E. Berry & Riina está localizada en los Andes occidentales de Ecuador y es hermana del clado de Croton sect. Adenophyllum Griseb. Croton abonari Riina & P.E. Berry se conoce de una sola localidad en la Amazonia de Brasil; es similar tanto a C. sampatik Müll. Arg. y a miembros de la sección Cuneati (G.L. Webster) Riina & P.E. Berry, pero C. abonari se puede diferenciar de ambos grupos por varios caracteres morfológicos distintivos

SINOPSIS DE CROTON (EUPHORBIACEAE) EN LOS ANDES DE MÉRIDA, VENEZUELA

Se realizó una sinopsis taxonómica del género Croton en los Andes de Mérida, Venezuela. Se analizaron caracteres vegetativos en 245 especímenes y se hizo un análisis de agrupamiento que resultó en la identificación de 21 grupos discretos a los cuales les fueron asignadas las identidades taxonómicas específicas más apropiadas. De estas 21 especies, C. pedicellatus representa un nuevo registro para Venezuela, C. fragilis, C. speciosus y C. redolens son nuevos registros para la región andina. Se proponen 2 nuevos sinónimos (C. chamanus bajo C. conduplicatus y C. timotensis bajo C. pungens) y se designan 3 lectotipos (C. pungens, C. ovalifolius y C. speciosus). Se discuten las relaciones entre las especies y se incluye una clave para su identificación

Euphorbiaceae endémicas del Perú

La familia Euphorbiaceae es reconocida en el Perú por presentar 61 géneros y 323 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004), mayormente arbustos y árboles. En este trabajo se reconoce 47 especies y dos variedades como endemismos peruanos en 19 géneros. El género Croton es el más numeroso en especies endémicas. Los taxones endémicos ocupan varias regiones, entre ellas Bosques Húmedos Amazónicos, Mesoandina y Bosques Muy Húmedos Montanos, entre los 110 y 3200 m de altitud. Se aplicaron las categorías y criterios de la UICN a 33 taxones. Tres especies se encuentran representadas en el Sistema Nacional de Áreas Naturales Protegidas por el Estado.The Euphorbiaceae are represented in Peru by 61 genera and 323 species (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004), mainly shrubs and trees. Here we recognize as Peruvian endemics 47 species and two varieties in 19 genera. Croton is the genus with the largest number of endemic species. Endemic Euphorbiaceae are found in several regions, including Humid Lowland Amazonian Forests, Mesoandean and Very Humid Montane Forests, between 110 and 3200 m elevation. We applied IUCN categories and criteria to 33 taxa. Three endemic Euphorbiaceae species have been registered to date within Peru’s protected areas system

Sectional rearrangement of arborescent clades of Croton (Euphorbiaceae) in South America: Evolution of arillate seeds and a new species, Croton domatifer

Most of the arborescent Croton species in the New World were treated by Webster as belonging either to C. sect. Cyclostigma Griseb. or C. sect. Luntia (Neck. ex Raf.) G.L. Webster. The circumscription of C. sect. Cyclostigma has been treated recently. In this paper we focus on C. sect. Luntia, which was subdivided by Webster into two subsections, C. subsect. Matourenses and subsect. Cuneati. Using chloroplast trnL‐F and nuclear ITS DNA sequence data, morphology and a broader sampling of additional Croton lineages, we found that the two subsections are not closely related and form distinct monophyletic groups. Substantial morphological differences support the molecular data. A taxonomic recircumscription of the two subsections, elevated to sectional level, is proposed. A key and taxonomic revision, with new synonyms, is provided for C. sect. Cuneati; together with the description of a new species from the coastal mountains of Venezuela, Croton domatifer. The new species is the only one in the genus known to possess leaf domatia. We infer that species in the Cuneati clade have lost the typical Croton caruncle, and some of them have evolved a different, specialized type of aril. We hypothesize that the arillate seeds are an adaptation to dispersal by fish in the Orinoco and Amazon river basins.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147226/1/tax594014.pd

A molecular phylogeny and classification of the largely succulent and mainly African Euphorbia subg. Athymalus (Euphorbiaceae)

Euphorbia subg. Athymalus consists of approximately 150 species and is one of the four main lineages that comprise the species–rich genus Euphorbia. Most species in the subgenus are stem succulents with greatly reduced leaves, but there are also leafy herbs, shrubs, trees and geophytes. The subgenus is restricted to arid regions of the Old World. Most species are found in sub–Saharan Africa, with one in Macaronesia and adjacent parts of western Africa, a few in the Arabian Peninsula (one of which extends into Iran) and one native to Madagascar. Twenty–three species are endemic to the northeastern Horn of Africa (SE Ethiopia, Socotra, Somalia), while 72 species are restricted to southern Africa (including Botswana, Lesotho, Namibia, South Africa and Swaziland). Sixty of those are endemic to South Africa alone, where they are particularly associated with the semi–arid west and south of the country in the Greater Cape Floristic Region and the Nama Karoo Region. We sampled 88 species and analyzed data from the nuclear ribosomal ITS and plastid ndhF regions. Analyses of the separate and combined datasets produced phylogenies that confirm the monophyly of E. subg. Athymalus and the placement of E. antso from Madagascar as sister to the rest of the subgenus. Our analyses also show that the subgenus consists of a grade of early–diverging lineages that are relatively poor in species and that the major radiation of succulent species in southern Africa forms a highly supported clade (E. sect. Anthacanthae). Species–level relationships within this southern African clade, however, remain largely unresolved. Our phylogenetic hypotheses allow us to propose a new classification for E. subg. Athymalus where seven sections are recognized, two of which are newly described. The large southern African E. sect. Anthacanthae is further divided into five subsections, and four series are recognized in E. subsect. Florispinae.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147157/1/tax6269.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147157/2/tax6269-sup-001-pdf.pd

Molecular phylogenetics and classification of Euphorbia subgenus Chamaesyce (Euphorbiaceae)

Euphorbia subg. Chamaesyce contains around 600 species and includes the largest New World radiation within the Old World–centered genus Euphorbia. It is one of the few plant lineages to include members with C3, C4 and CAM photosynthesis, showing multiple adaptations to warm and dry habitats. The subgenus includes North American–centered groups that were previously treated at various taxonomic ranks under the names of “Agaloma,,, “Poinsettia”, and “Chamaesyce”. Here we provide a well–resolved phylogeny of Euphorbia subg. Chamaesyce using nuclear ribosomal ITS and chloroplast ndhF sequences, with substantially increased taxon sampling compared to previous studies. Based on the phylogeny, we discuss the Old World origin of the subgenus, the evolution of cyathial morphology and growth forms, and then provide a formal sectional classification, with descriptions and species lists for each section or subsection we recognize.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146846/1/tax614005.pd

Botanical novelties from Sierra de Maigualida, southern Venezuela. II

Four new species, Siphocampylus acanthidiotrichus J.R. Grande (Campanulaceae), Phyllanthus huberi Riina & P.E. Berry (Phyllanthaceae), Sohnreyia maigualidensis J.R. Grande & Kallunki (Rutaceae), and Turnera maigualidensis J.R. Grande & Arbo (Turneraceae) are described and illustrated from the summit areas of Sierra de Maigualida in the Guayana Highlands of southern Venezuela. To date, one genus, 32 spe cies, one subspecies, and one variety of angiosperms are known only from the Maigualida meadows and shrublands, between 1800 m and the highest elevation areas at 2400 m. Here we describe the first iteroparous species for the genus Sohnreyia K. Krause, a Turnera L. species with apically villose, apiculate petals, and a Siphocampylus Pohl species with aculeiform hairs and pinnatisect leaves. The new species, Siphocampylus acanthidiotrichus, together with S. tillettii Steyerm., represents a morphologically distinct subgroup within the genus.Se describen e ilustran cuatro especies nuevas procedentes de las cumbres de la Sierra de Maigualida: Siphocampylus acanthidiotrichus J.R. Grande (Campanulaceae), Phyllanthus huberi Riina & P.E. Berry (Phyllanthaceae), Sohnreyia maigualidensis J.R. Grande & Kallunki (Rutaceae) y Turnera maigualidensis J.R. Grande & Arbo (Turneraceae). Hasta ahora un género, 32 especies, una subespecie y una variedad de angiospermas se conocen exclusivamente de la Sierra de Maigualida, y todas ellas proceden de herbazales y arbustales desarrollados entre los 1800 m y las áreas más altas, a 2400 m. Aquí, se describen por primera vez una especie iterópara del género Sohnreyia K. Krause (Rutaceae), una especie de Turnera L. con pétalos apiculados apicalmente vilosos y una especie de Siphocampylus Pohl con pelos aculeiformes y hojas pinnatisectas. La nueva especie Siphocampylus acanthidiotrichus representa, junto a S. tillettii Steyerm., un subgrupo morfológicamente distinto dentro del género.Fil: Grande, José R.. Universidad Central de Venezuela. Facultad de Ciencias; VenezuelaFil: Kallunki, Jacquelyn. New York Botanical Garden; Estados UnidosFil: Arbo, Maria Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); ArgentinaFil: Berry, Paul E.. University Of Michigan; Estados UnidosFil: Huber, Otto. Universidad Central de Venezuela; VenezuelaFil: Riina, Ricarda. University Of Michigan; Estados Unidos. Consejo Superior de Investigaciones Cientificas. Real Jardin Botanico; Españ

New 3,4-seco-ent-kaurene dimers from Croton micans.

From the stems of Croton micans Sw., five new 3,4- seco-ent-kaurene dimers: micansinoic acid (1), isomicansinoic acid (2), and the dimethyl (3), monomethyl (4) and monoethyl ester (5) of micansinoic acid were isolated. The structures of the new compounds were elucidated by spectroscopic data interpretation, mainly 1D and 2D NMR experiments and MS. These compounds are the first 3,4- seco-ent-kaurene dimers from a Croton species

Phylogenetics, morphological evolution, and classification of Euphorbia subgenus Euphorbia

Euphorbia subg. Euphorbia is the largest and most diverse of four recently recognized subgenera within Euphorbia and is distributed across the tropics and subtropics. Relationships within this group have been difficult to discern due mainly to homoplasious morphological characters and inadequate taxon sampling in previous phylogenetic studies. Here we present a phylogenetic analysis of E. subg. Euphorbia, using one nuclear and two plastid regions, for the most complete sampling of molecular sequence data to date. We assign 661 species to the subgenus and show that it is comprised of four highly supported clades, including a single New World clade and multiple independent lineages on Madagascar. Using this phylogenetic framework we discuss patterns of homoplasy in morphological evolution and general patterns of biogeography. Finally, we present a new sectional classification of E. subg. Euphorbia comprising 21 sections, nine of them newly described here.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147178/1/tax6225-sup-003-pdf.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147178/2/tax6225.pd