The Experts below are selected from a list of 33 Experts worldwide ranked by ideXlab platform
Walter S. Judd - One of the best experts on this subject based on the ideXlab platform.
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Two New Species of Schoenocaulon (Liliales: Melanthiaceae) from Mexico Supported by ITS Sequence Data
Systematic Botany, 2008Co-Authors: Wendy B. Zomlefer, Walter S. JuddAbstract:Abstract Two new species of Schoenocaulon from Mexico, S. framei and S. oaxacense, are delimited by analyses of ITS sequence data and characterized by distinct morphology and biogeography. Schoenocaulon framei, a segregate from the polyphyletic S. comatum s.l., is described for the first time; S. oaxacense is elevated to species rank, based on S. caricifolium var. oaxacense, one of two monophyletic varieties comprising polyphyletic S. caricifolium s.l. Schoenocaulon framei is distinguished by unusual sunken stomata on the abaxial leaf surface and ligulate, weakly auriculate tepals, each with a smooth basal nectariferous zone; the basal perigonal gland of S. oaxacense is a glandular depression, and its tepals are ligulate. Both new species also are well-supported cladospecies with ITS sequence data according to the apomorphic species concept. Our results confirm the importance of molecular phylogenetic analyses in decisions relating to species circumscription, especially when such analyses are carefully co...
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Infrageneric phylogeny of Schoenocaulon (Liliales: Melanthiaceae) with clarification of cryptic species based on ITS sequence data and geographical distribution
American journal of botany, 2006Co-Authors: Wendy B. Zomlefer, Norris H Williams, W. Mark Whitten, Walter S. JuddAbstract:As currently defined, the 24 species of Schoenocaulon occur in three disjunct areas: north central Florida (one species, S. dubium), southern Peru (portion of the range of S. officinale), and the region from southeastern New Mexico-Texas south to Venezuela; the 20 species endemic to Mexico are geographically restricted. Species delimitations, often based on tepal morphology, have been problematic. Our analyses of ITS sequence data for all 27 species and infraspecific taxa support recognition of two new species and recircumscription and placement of elements of the polyphyletic S. ghiesbreghtii and S. mortonii complexes. For taxa with adequate sampling, our data also indicate 11-12 cladospecies and 3-6 metaspecies according to the apomorphic species concept. The resolved phylogeny, correlated with geography and morphology, allows insight into biogeographical diversification and the evolution of some unusual morphological characters within the genus, such as nectary differentiation and tepal margin type.
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generic circumscription and relationships in the tribe melanthieae liliales melanthiaceae with emphasis on zigadenus evidence from its and trnl f sequence data
American Journal of Botany, 2001Co-Authors: Wendy B. Zomlefer, Norris H Williams, Mark W Whitten, Walter S. JuddAbstract:The circumscription and relationships of genera within the tribe Melanthieae (29 representative taxa) were evaluated using parsimony analyses of ITS (nuclear ribosomal) and trnL-F (plastid) DNA sequence data, alone and in combination. Proposed new generic circumscriptions, strongly supported by the tree statistics and topologies in all analyses, are correlated with potential morphological synapomorphies at the proper level of universality. Based on the molecular cladograms, Stenanthium is biphyletic, and the traditional Zigadenus s.1. (sensu lato) is polyphyletic. Amianthium and Schoenocaulon are distinct entities; the Veratrum complex is conservatively treated as one large monophyletic genus (including Melanthium). Although some generic relationships are not highly resolved, the analyses provide strong support for Zigadenus glaberrimus as sister to the rest of the tribe, and Amianthium muscitoxicum as closely related to Veratrum s.l. As a result of these analyses, seven genera (some with novel circumscription) are recognized within the tribe Melanthieae: Amianthium, Anticlea, Schoenocaulon, Stenanthium, Toxicoscordion, Veratrum, and Zigadenus.
Wendy B. Zomlefer - One of the best experts on this subject based on the ideXlab platform.
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Two New Species of Schoenocaulon (Liliales: Melanthiaceae) from Mexico Supported by ITS Sequence Data
Systematic Botany, 2008Co-Authors: Wendy B. Zomlefer, Walter S. JuddAbstract:Abstract Two new species of Schoenocaulon from Mexico, S. framei and S. oaxacense, are delimited by analyses of ITS sequence data and characterized by distinct morphology and biogeography. Schoenocaulon framei, a segregate from the polyphyletic S. comatum s.l., is described for the first time; S. oaxacense is elevated to species rank, based on S. caricifolium var. oaxacense, one of two monophyletic varieties comprising polyphyletic S. caricifolium s.l. Schoenocaulon framei is distinguished by unusual sunken stomata on the abaxial leaf surface and ligulate, weakly auriculate tepals, each with a smooth basal nectariferous zone; the basal perigonal gland of S. oaxacense is a glandular depression, and its tepals are ligulate. Both new species also are well-supported cladospecies with ITS sequence data according to the apomorphic species concept. Our results confirm the importance of molecular phylogenetic analyses in decisions relating to species circumscription, especially when such analyses are carefully co...
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Infrageneric phylogeny of Schoenocaulon (Liliales: Melanthiaceae) with clarification of cryptic species based on ITS sequence data and geographical distribution
American journal of botany, 2006Co-Authors: Wendy B. Zomlefer, Norris H Williams, W. Mark Whitten, Walter S. JuddAbstract:As currently defined, the 24 species of Schoenocaulon occur in three disjunct areas: north central Florida (one species, S. dubium), southern Peru (portion of the range of S. officinale), and the region from southeastern New Mexico-Texas south to Venezuela; the 20 species endemic to Mexico are geographically restricted. Species delimitations, often based on tepal morphology, have been problematic. Our analyses of ITS sequence data for all 27 species and infraspecific taxa support recognition of two new species and recircumscription and placement of elements of the polyphyletic S. ghiesbreghtii and S. mortonii complexes. For taxa with adequate sampling, our data also indicate 11-12 cladospecies and 3-6 metaspecies according to the apomorphic species concept. The resolved phylogeny, correlated with geography and morphology, allows insight into biogeographical diversification and the evolution of some unusual morphological characters within the genus, such as nectary differentiation and tepal margin type.
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generic circumscription and relationships in the tribe melanthieae liliales melanthiaceae with emphasis on zigadenus evidence from its and trnl f sequence data
American Journal of Botany, 2001Co-Authors: Wendy B. Zomlefer, Norris H Williams, Mark W Whitten, Walter S. JuddAbstract:The circumscription and relationships of genera within the tribe Melanthieae (29 representative taxa) were evaluated using parsimony analyses of ITS (nuclear ribosomal) and trnL-F (plastid) DNA sequence data, alone and in combination. Proposed new generic circumscriptions, strongly supported by the tree statistics and topologies in all analyses, are correlated with potential morphological synapomorphies at the proper level of universality. Based on the molecular cladograms, Stenanthium is biphyletic, and the traditional Zigadenus s.1. (sensu lato) is polyphyletic. Amianthium and Schoenocaulon are distinct entities; the Veratrum complex is conservatively treated as one large monophyletic genus (including Melanthium). Although some generic relationships are not highly resolved, the analyses provide strong support for Zigadenus glaberrimus as sister to the rest of the tribe, and Amianthium muscitoxicum as closely related to Veratrum s.l. As a result of these analyses, seven genera (some with novel circumscription) are recognized within the tribe Melanthieae: Amianthium, Anticlea, Schoenocaulon, Stenanthium, Toxicoscordion, Veratrum, and Zigadenus.
Norris H Williams - One of the best experts on this subject based on the ideXlab platform.
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Infrageneric phylogeny of Schoenocaulon (Liliales: Melanthiaceae) with clarification of cryptic species based on ITS sequence data and geographical distribution
American journal of botany, 2006Co-Authors: Wendy B. Zomlefer, Norris H Williams, W. Mark Whitten, Walter S. JuddAbstract:As currently defined, the 24 species of Schoenocaulon occur in three disjunct areas: north central Florida (one species, S. dubium), southern Peru (portion of the range of S. officinale), and the region from southeastern New Mexico-Texas south to Venezuela; the 20 species endemic to Mexico are geographically restricted. Species delimitations, often based on tepal morphology, have been problematic. Our analyses of ITS sequence data for all 27 species and infraspecific taxa support recognition of two new species and recircumscription and placement of elements of the polyphyletic S. ghiesbreghtii and S. mortonii complexes. For taxa with adequate sampling, our data also indicate 11-12 cladospecies and 3-6 metaspecies according to the apomorphic species concept. The resolved phylogeny, correlated with geography and morphology, allows insight into biogeographical diversification and the evolution of some unusual morphological characters within the genus, such as nectary differentiation and tepal margin type.
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generic circumscription and relationships in the tribe melanthieae liliales melanthiaceae with emphasis on zigadenus evidence from its and trnl f sequence data
American Journal of Botany, 2001Co-Authors: Wendy B. Zomlefer, Norris H Williams, Mark W Whitten, Walter S. JuddAbstract:The circumscription and relationships of genera within the tribe Melanthieae (29 representative taxa) were evaluated using parsimony analyses of ITS (nuclear ribosomal) and trnL-F (plastid) DNA sequence data, alone and in combination. Proposed new generic circumscriptions, strongly supported by the tree statistics and topologies in all analyses, are correlated with potential morphological synapomorphies at the proper level of universality. Based on the molecular cladograms, Stenanthium is biphyletic, and the traditional Zigadenus s.1. (sensu lato) is polyphyletic. Amianthium and Schoenocaulon are distinct entities; the Veratrum complex is conservatively treated as one large monophyletic genus (including Melanthium). Although some generic relationships are not highly resolved, the analyses provide strong support for Zigadenus glaberrimus as sister to the rest of the tribe, and Amianthium muscitoxicum as closely related to Veratrum s.l. As a result of these analyses, seven genera (some with novel circumscription) are recognized within the tribe Melanthieae: Amianthium, Anticlea, Schoenocaulon, Stenanthium, Toxicoscordion, Veratrum, and Zigadenus.
W. Mark Whitten - One of the best experts on this subject based on the ideXlab platform.
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Infrageneric phylogeny of Schoenocaulon (Liliales: Melanthiaceae) with clarification of cryptic species based on ITS sequence data and geographical distribution
American journal of botany, 2006Co-Authors: Wendy B. Zomlefer, Norris H Williams, W. Mark Whitten, Walter S. JuddAbstract:As currently defined, the 24 species of Schoenocaulon occur in three disjunct areas: north central Florida (one species, S. dubium), southern Peru (portion of the range of S. officinale), and the region from southeastern New Mexico-Texas south to Venezuela; the 20 species endemic to Mexico are geographically restricted. Species delimitations, often based on tepal morphology, have been problematic. Our analyses of ITS sequence data for all 27 species and infraspecific taxa support recognition of two new species and recircumscription and placement of elements of the polyphyletic S. ghiesbreghtii and S. mortonii complexes. For taxa with adequate sampling, our data also indicate 11-12 cladospecies and 3-6 metaspecies according to the apomorphic species concept. The resolved phylogeny, correlated with geography and morphology, allows insight into biogeographical diversification and the evolution of some unusual morphological characters within the genus, such as nectary differentiation and tepal margin type.
Dawn Frame - One of the best experts on this subject based on the ideXlab platform.
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chromosome studies in Schoenocaulon liliacea melanthiaeae a relictgenus
Anales del Instituto de Biología. UNAM. Serie botánica, 2001Co-Authors: Dawn FrameAbstract:SE PRESENTAN LOS RESULTADOS DE LOS RECUENTOS CROMOSOMICOS DE OCHO TAXA, REPRESENTANTES DE SIETE ESPECIES DE Schoenocaulon (LILIACEAE: MELANTHIEAE), UN GENERO PRINCIPALMENTE MEXICANO. UNA ESPECIE (S. TENORIOI) PRESENTA UNA CADENA DE TRES CROMOSOMAS, CUYO POSIBLE ORIGEN SE DISCUTE. SE DESCRIBE BREVEMENTE LA MORFOLOGIA CARIOTIPICA GENERAL Y, JUNTO CON EL NUMERO CROMOSOMICO, SE CONSIDERA EN EL CONTEXTO DE OTRAS LILIACEAE CERCANAMENTE RELACIONADAS. ADEMAS, SE PRESENTAN HIPOTEOS DE TENDENCIAS EVOLUTIVAS AMPLIAS, BASADAS EN LA EN LA EVOLUCION CROMOSOMICA DE Schoenocaulon, CON MAS HACIA ESTRATEGIAS FUTURAS PARA LA PROTECCION Y CONSERVACION DE ESTAS PLANTAS.
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a conspectus of mexican melantiaceae including a description of new taxa of Schoenocaulon and zigadenus
Acta Botanica Mexicana, 1999Co-Authors: Dawn Frame, Adolfo Espejo, Ana Rosa LopezferrariAbstract:Seven new taxa of Schoenocaulon and one more of Zigadenus from Mexico are herein described. In addition, a brief description of the Mexican genera of Melanthiaceae and a key to genera and species known from Mexico are given.