New Euphorbiaceae from Mexico

This article contained descriptions of five new taxa of Mexican Euphorbiaceae. Euphorbia (subg. Agaloma) nayarensis is endemic to pine-oak woodland in the mountains of central Nayarit. It appears related to E. soobyi but differs by possessing linear to linear-ovate leaves. Croton varelae is also endemic to central Nayarit. A key was provided to distinguish this species, a member of sect. Geiseleria, from the seven other Mexican species of this section. Croton ramillatus var. magniglandulifer occurs in the states of Guerrero and Morelos. This new variety differs from var. ramillatus by the possession of larger petiolar glands. Croton michaelii occurs in Aguascalientes and Durango. It is uncertain to which section of Croton this species belongs. It resembles Croton yecorensis but is distinguished by possessing a lepidote indumentum and by lacking conspicuous stipitate glands. Croton disjunctus has been collected in Chihuahua and Aguascalientes, at localities separated by more than 600 km. This species appears to be most closely akin to Croton fruticulosus Torr., from which it is separated by glabrous, evident (vs. pubescent, nearly obsolete) stipules and multifid (vs. bifid) styles

Euphorbia (Subgen. Chamaesyce Sect. Anisophyllum) jaegeri, a Shrubby New Species from the Deserts of California, United States

Euphorbia jaegeri (Euphorbiaceae), an endemic to southeastern California, United States, is described as new and illustrated with photographs. It is known from two general locations, one in the Orocopia Mountains (Riverside County) and the other in the Marble Mountains and adjacent Bristol Mountains (San Bernardino County). The habitat is desert scrub on rocky hillsides and along arroyos, primarily in rock crevices or gravelly soils, at elevations from approximately 600 to 850 m. The new species belongs to Euphorbia subgen. Chamaesyce sect. Anisophyllum. It is distinguished by the combination of a shrubby habit and involucral appendages that are deeply parted into triangular to subulate segments. The exact affinities of the new species are not obvious, but it is compared with E. polycarpa and E. setiloba. With only four known occurrences, a fragmented distribution, and significant existing and potential threats to most of the populations, E. jaegeri is of high conservation concern

The Euphorbiaceae of Sonora, Mexico

This publication is an account of the Euphorbiaceae in the state of Sonora, México. Nineteen genera, 143 species, and three additional varieties are recorded for the state; three species expected within the state are also treated. One species of Acalypha and three species and one subspecies of Euphorbia are described. Dichotomous keys for the identification of genera and species are provided. Bibliographic citations, type information, synonyms, brief habit descriptions, times of reproduction, habitat preferences as well as elevational range within Sonora, geographical distribution, and representative specimens are given for each species. When appropriate, notes on uses, taxonomic or nomenclatural problems, and other points of interest are discussed

Meliosma mexicana (Sabiaceae), una especie nueva de la Sierra Madre Oriental de México

Meliosma mexicana (Sabiaceae) is described as a new species. It occurs in the Sierra Madre Oriental of Mexico in the states of Querétaro and Tamaulipas, growing primarily in cloud forest and humid pine-oak forest at elevations of 800 to 1900 m. It belongs to subg. Meliosma sect. Lorenzanea. It is most similar to M. dentata, which it apparently replaces in northeastern Mexico. Meliosma mexicana is distinguished from M. dentata in having essentially entire leaves, stipitate glandular trichomes that vary from red to blackish, and subglobose fruits 0.6 to 0.7(0.8) cm long.Se describe como especie nueva a Meliosma mexicana (Sabiaceae). Es endémica de la Sierra Madre Oriental de México en los estados de Querétaro y Tamaulipas. Crece desde los 800 hasta los 1900 m de altitud en el bosque mesófilo de montaña y el bosque de pino-encino húmedo. Pertenece al subg. Meliosma sect. Lorenzanea y es morfológicamente parecida a M. dentata, a la cual aparentemente remplaza en el noreste de México. Meliosma mexicana se distingue de M. dentata por tener hojas esencialmente enteras, glándulas estipitadas que varían de color rojizo a negruzco, y frutos subglobosos de 0.6 a 0.7(0.8) cm de largo

MELIOSMA MEXICANA (SABIACEAE), UNA ESPECIE NUEVA DE LA SIERRA MADRE ORIENTAL DE MÉXICO

Meliosma mexicana (Sabiaceae) is described as a new species. It occurs in the Sierra Madre Oriental of Mexico in the states of Querétaro and Tamaulipas, growing primarily in cloud forest and humid pine-oak forest at elevations of 800 to 1900 m. It belongs to subg. Meliosma sect. Lorenzanea. It is most similar to M. dentata, which it apparently replaces in northeastern Mexico. Meliosma mexicana is distinguished from M. dentata in having essentially entire leaves, stipitate glandular trichomes that vary from red to blackish, and subglobose fruits 0.6 to 0.7(0.8) cm long.Se describe como especie nueva a Meliosma mexicana (Sabiaceae). Es endémica de la Sierra Madre Oriental de México en los estados de Querétaro y Tamaulipas. Crece desde los 800 hasta los 1900 m de altitud en el bosque mesófilo de montaña y el bosque de pino-encino húmedo. Pertenece al subg. Meliosma sect. Lorenzanea y es morfológicamente parecida a M. dentata, a la cual aparentemente remplaza en el noreste de México. Meliosma mexicana se distingue de M. dentata por tener hojas esencialmente enteras, glándulas estipitadas que varían de color rojizo a negruzco, y frutos subglobosos de 0.6 a 0.7(0.8) cm de largo

Dos nuevas especies de Euphorbia sect. Nummulariopsis (Euphorbiaceae) para Sudamérica

Two new species of sect. Nummulariopsis, Euphorbia guaraniorum and E. cordeiroae, are described and illustrated. Euphorbia guaraniorum appears to be related to E. portulacoides and is distinguished by its densely arranged ensiform leaves. It is known only from the Yacyretá and Ybycui Islands in southern Paraguay. Euphorbia cordeiroae, occurs in the state of Goiás, Brazil, and is similar to E. stenophylla, from which it differs in its higher stature and very narrow and loosely arranged leaves.Dos nuevas especies de la sección Nummulariopsis, Euphorbia guaraniorum y E. cordeiroae son descritas e ilustradas. Euphorbia guaraniorum parece estar relacionada con E. portulacoides, de la que se distingue por sus hojas ensiformes densamente agrupadas y se conoce solo de las islas Yacyretá e Ybycui, en el sur de Paraguay; E. cordeiroae, conocida sólo del estado de Goiás, Brasil, se compara con E. stenophylla, de la que se diferencia por ser una planta más alta y por sus hojas extremadamente delgadas y con un arreglo laxo

Divergent genetic mechanisms underlie reversals to radial floral symmetry from diverse zygomorphic flowered ancestors

Malpighiaceae possess flowers with a unique bilateral symmetry (zygomorphy), which is a hypothesized adaptation associated with specialization on neotropical oil bee pollinators. Gene expression of two representatives of the CYC2 lineage of floral symmetry TCP genes, CYC2A and CYC2B, demarcate the adaxial (dorsal) region of the flower in the characteristic zygomorphic flowers of most Malpighiaceae. Several clades within the family, however, have independently lost their specialized oil bee pollinators and reverted to radial flowers (actinomorphy) like their ancestors. Here, we investigate CYC2 expression associated with four independent reversals to actinomorphy. We demonstrate that these reversals are always associated with alteration of the highly conserved CYC2 expression pattern observed in most New World (NW) Malpighiaceae. In NW Lasiocarpus and Old World (OW) Microsteria, the expression of CYC2-like genes has expanded to include the ventral region of the corolla. Thus, the pattern of gene expression in these species has become radialized, which is comparable to what has been reported in the radial flowered legume clade Cadia. In striking contrast, in NW Psychopterys and OW Sphedamnocarpus, CYC2-like expression is entirely absent or at barely detectable levels. This is more similar to the pattern of CYC2 expression observed in radial flowered Arabidopsis. These results collectively indicate that, regardless of geographic distribution, reversals to similar floral phenotypes in this large tropical angiosperm clade have evolved via different genetic changes from an otherwise highly conserved developmental program

Una especie nueva de Acidocroton Sección Ophellantha (Euphorbiaceae) de Tabasco, México

The new species Acidocroton madrigalensis is described and illustrated from the state of Tabasco, Mexico. It is known only from the Sierra El Madrigal and the Cerro La Campana, where it is a frequent component of the under story of tropical rain forest, occurring on limestone outcrops. It belongs to section Ophellantha and is characterized by its diminutive, non-spinous stipules, large leaves that are shortly petiolate, and staminate flowers with 20 to 35 stamens. A table is presented that provides the principal differences among A. madrigalensis and the other two species of the genus present in Mexico, A. spinosus y A. steyermarkii.Se describe e ilustra a Acidocroton madrigalensis, una nueva especie del estado de Tabasco, México. Se conoce solamente de la Sierra El Madrigal y el Cerro La Campana, en donde es un componente abundante del estrato bajo en la selva alta perennifolia sobre afloramientos de roca caliza. Pertenece a la sección Ophellantha y se caracteriza por sus diminutas estípulas no espiniformes, hojas grandes y cortamente pecioladas y por tener flores estaminadas con 20 a 35 estambres. Se presenta un cuadro mostrando las diferencias principales entre A. madrigalensisy las otras dos especies del género conocidas de México, A. spinosus y A. steyermarkii

Are spurred cyathia a key innovation? Molecular systematics and trait evolution in the slipper spurges (Pedilanthus clade: Euphorbia, Euphorbiaceae)

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141662/1/ajb20493.pd