LUNDELLIA 15 COVER

Journal of the Plant Resources Center of the University of Texas at Austin
Number 15 — December 2012
[Published: 7 December 2012]


Contents:

Preliminary Phylogeny of Diplostephium (Asteraceae): Speciation Rate and Character Evolution
Oscar M. Vargas & Santiago Madriñán View Abstract — Download article (4.3 MB)
[File with high-resolution images (13.8 MB)]

Justicia salasiae, a New Species of Acanthaceae from Oaxaca, Mexico
Thomas F. Daniel and Emily J. Lott View Abstract — Download article (1.6 MB)
[File with high-resolution images (21.9 MB)]

Taxonomic Status of Rhynchosia diversifolia var. prostrata (Fabaceae)
Billie L. Turner View Abstract — Download article (1.5 MB)

Notes on Wissadula (Malvaceae) with the Description of Two New Species
Paul A. Fryxell View Abstract — Download article (1.4 MB)
[File with high-resolution images (19.8 MB)]

Four New Species of the Genus Aloysia (Verbenaceae)
Stephen J. Siedo View Abstract — Download article (3.4 MB)
[File with high-resolution images (158 MB)]

Polygala minima (Polygalaceae) in Western Mexico
Tom Wendt View Abstract — Download article (1.5 MB)

Croton pascualii (Euphorbiaceae s.s.), a New Arborescent Croton with an Accrescent Calyx from the Pacific Slope of Oaxaca, Mexico
Emily J. Lott & Martha Martínez-Gordillo View Abstract — Download article (709 KB)

Abstracts

Preliminary Phylogeny of Diplostephium (Asteraceae): Speciation Rate and Character Evolution
Oscar M. Vargas & Santiago Madriñán
1—15

Abstract: Diplostephium comprises 111 neotropical species that live in high elevation habitats from Costa Rica to Chile. Primarily Andean, the genus seems to have undergone an adaptive radiation indicated by its high number of species, broad morphological variation, and diversification primarily in an ecosystem (páramo) that formed within the last 2–5 my. Internal transcriber spacer (ITS) sequences and several chloroplast markers, rpoB, rpoC1, and psbA-trnH were sequenced in order to infer a preliminary phylogeny of the genus. The chloroplast regions showed no significant variation within the genus. New ITS data were therefore analyzed together with published sequences for generating a topology. Results suggest that Diplostephium and other South American genera comprise a polytomy within which a previously described North American clade is nested. Monophyly of Diplostephium was not supported, but the formation of a main crown clade using different methods of analysis suggests that at least a good portion of the genus is monophyletic. A Shimodaira-Hasegawa test comparing the topology obtained and a constrained one forcing Diplostephium to be monophyletic showed no significant difference between them. Monophyly of some of the previously proposed series of the genus was not supported by the phylogenetic tree. Morphological character mapping results suggest that the high Andean forest tree species are derived from shrubby páramo-puna ancestors, contradicting previous hypotheses about morphological evolution of the genus, and documenting an atypical trend of downslope diversification in páramo plants.
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Justicia salasiae, a New Species of Acanthaceae from Oaxaca, Mexico
Thomas F. Daniel and Emily J. Lott
16—21

Abstract: Justicia salasiae, a new species from tropical deciduous forests in the Sierra Madre del Sur of southern Oaxaca, Mexico is described and illustrated. The species is distinctive by its panicles of spikes bearing elongate bracts and its tuberculate seeds that bear minute trichomes on the tubercles.

Resumen: Se describe e ilustra Justicia salasiae como especie nueva de selva baja caducifolia de la Sierra Madre del Sur, en el sur de Oaxaca, México. Se distingue la especie por sus panículas de espigas con las brácteas alargadas y sus semillas tuberculadas con tricomas minúsculas en los tubérculos.

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Taxonomic Status of Rhynchosia diversifolia var. prostrata (Fabaceae)
Billie L. Turner
22—25

Abstract: Rhynchosia diversifolia var. prostrata, sensu Grear (1978), is elevated to specific status where it is given a new name, Rhynchosia bicentrica, nom. and stat. nov., there being an earlier R. prostrata. Reasons for the elevation are provided, along with maps showing its amphitropical distribution.
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Notes on Wissadula (Malvaceae) with the Description of Two New Species
Paul A. Fryxell
26—34

Abstract: Some historical considerations concerning the identity of Wissadula stellata (Cav.) K. Schum., lectotypifications of Sida stellata Cav. and W. fuscorosea Ulbr., the description of two new species (W. ecuadoriensis and W. macrocarpa), and the discussion of the legitimacy of a name widely but incorrectly used in Wissadula Medik., W. macrantha R.E.Fr., nom. illegit., are presented.

Resumen: Se presentan una discusión de la historia de la identidad de Wissadula stellata (Cav.) K. Schum., las lectotipificaciónes de Sida stellata Cav. y W. fuscorosea Ulbr., las descripciones de dos especies nuevas (W. ecuadoriensis y W. macrocarpa), y una discussión del nombre W. macrantha R.E.Fr., un nombre muy utilizado a pesar de ser ilegítimo.

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Four New Species of the Genus Aloysia (Verbenaceae)
Stephen J. Siedo
35—46

Abstract: Four new species of the genus Aloysia are described: A. arequipensis, A. coalcomana, A. cordata, and A. velutina. A key to the species and a brief discussion of each novelty is included along with a key to the New World genera of the tribe Lantaneae.

Resumen: Se describen cuatro especies nuevas del género Aloysia: A. arequipensis, A. coalcomana, A. cordata, y A. velutina. Se incluyen una clave para las especies y una breve análisis de cada novedad, junto con una clave para los géneros del Nuevo Mundo de la tribu Lantaneae.

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Polygala minima (Polygalaceae) in Western Mexico
Tom Wendt
47—53

Abstract: The widespread Neotropical species Polygala glochidiata has traditionally been considered the only Polygala with uncinate seed hairs to occur in Mexico. A second species with such hairs is shown to occur partly sympatrically with P. glochidiata in Jalisco and Nayarit and is referred to P. minima, heretofore considered to be a species restricted to southern Brazil, Paraguay, and northern Argentina. A single collection from the state of México is also referred to P. minima, while the situation from Oaxaca southeastward into Central America is more complex. Patterns of variation in the P. glochidiata complex require further study, but data are presented to dispute the synonymization of P. minima into P. glochidiata by Bernardi.

Resumen: Polygala glochidiata, especie neotropical de amplia distribución, ha sido considerada tradicionalmente como la única especie mexicana de Polygala con pelos uncinados en la semilla. Sin embargo, una segunda especie con pelos de este tipo se encuentra en Jalisco y Nayarit y es parcialmente simpátrica con P. glochidiata. Se considera a esta segunda especie como coespecífica con P. minima, una especie anteriormente tratada como restringida al sur de Brasil, Paraguay y el norte de Argentina. Además se considera una sola recolección del estado de México como P. minima, mientras que la situación desde Oaxaca hasta Centroamérica es más complicada. Los patrones de variación en el complejo de P. glochidiata requieren más estudio; sin embargo, se presentan datos en contra de la sinonimización, efectuada por Bernardi, de P. minima con P. glochidiata.

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Croton pascualii (Euphorbiaceae s.s.), a New Arborescent Croton with an Accrescent Calyx from the Pacific Slope of Oaxaca, Mexico
Emily J. Lott & Martha Martínez-Gordillo
54—58

Abstract: A new arborescent species of Croton with accrescent pistillate calyx, Croton pascualii, is described and illustrated from the Pacific Slope of Oaxaca, Mexico. It has certain characteristics in common with Croton oerstedianus, a species included in the section Corylocroton. The proposed new species is characterized by its unisexual cymules, large and broadly ovate imbricate sepals of the pistillate flowers, and capsules ca 12 mm long. The foliage and resin of the new species have a pleasant, persistent aromatic fragrance suggestive of Quararibea or of celery (Apium graveolens). Croton pascualii is thus far known only from the Tropical Moist Semi-Evergreen Forest (selva mediana subperennifolia) of the Pacific Slope of Oaxaca, and has been collected in flower from June to September.

Resumen: Se describe Croton pascualii como una especie nueva de la selva mediana subperennifolia de la vertiente del Pacífico de Oaxaca, México. La especie nueva tiene ciertas características en común con Croton oerstedianus, de la sección Corylocroton. Sin embargo, la nueva especie se distingue, de otras descritas para México y Centroamérica, por las siguientes caracteres: los sépalos de las flores pistiladas grandes, ovados, imbricados y acrescentes. El follaje y la resina de la nueva especie tienen un aroma agradable parecido al de Quararibea (Malvaceae) o a apio (Apium graveolens). Croton pascualii hasta la fecha se conoce solamente de la vertiente del Pacífico del estado de Oaxaca, donde se ha colectado con flor de junio a septiembre.

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