Showing papers in "Taxon in 1994"
281 citations
TL;DR: Many plant species are likely to be paraphyletic, and predictably a species classification based on the criterion of monophyly is unlikely to be an effective tool for describing and ordering biological diversity.
Abstract: transforming widespread population systems through gene flow or selection, allopatric speciation by subdivision is likely to be less frequent than geographically local models of speciation. Low levels of gene flow will also increase the time required for the progenitor species to achieve monophyly. Thus, many plant species are likely to be paraphyletic, and predictably a species classification based on the criterion of monophyly is unlikely to be an effective tool for describing and ordering biological diversity.
224 citations
TL;DR: The Flora of North America North of Mexico, to be published in 30 volumes, is a synoptic floristic account of the plants of Greenland, St. Pierre and Miquelon, Canada, and the continental United States of America.
Abstract: The Flora of North America North of Mexico, to be published in 30 volumes, is a synoptic floristic account of the plants of Greenland, St. Pierre and Miquelon, Canada, and the continental United States of America (including the Florida Keys and the Aleutian Islands). The Flora includes accepted names, literature citations, selected synonyms, identification keys, descriptions, chromosome numbers, summaries of habitats and geographic ranges, phenological information, conservation status, and significant biological observations, as well as maps and illustrations. Each volume contains a bibliography and an index to taxa treated.
112 citations
Journal Article•
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86 citations
TL;DR: The present chromosome number survey is based on the holdings of the National Clonal Germplasm Repository in Corvallis, which houses a world Mentha collection which includes most of the known taxa.
Abstract: Summary Chambers, H. L. & Hummer, K. E.: Chromosome counts in the Mentha collection at the USDAARS National Clonal Germplasm Repository. - Taxon 43: 423-432. 1994. - ISSN 0040-0262. The present chromosome number survey is based on the holdings of the National Clonal Germplasm Repository in Corvallis, which houses a world Mentha collection which includes most of the known taxa. The survey complements previously published counts and provides information about 73 accessions that are available to researchers. It includes chromosome counts for two accessions of M. australis, a previously uncounted Australian endemic, and accessions of M. japonica, M. diemenica, and M. cunninghamii, taxa with but one or a few published previous
52 citations
TL;DR: The exclusion of the Fockeeae has helped to reduce considerably the heterogeneity of the Marsdenieae and the monophyly of the remaining taxa still needs confirmation, and Bruyns & Forster (1991) have summarized this information and their system has found wide acceptance.
Abstract: Since the separation of 36 genera of Asclepiadaceae from the Apocynaceae by Brown (1810), the number of genera in the family has steadily increased. Especially the works of Decaisne (1838, 1844) and Bentham (1876) have added numerous new species and genera. The presently recognized c. 250 genera have been classified on a worldwide basis in a number of systems, differing to various degrees in character emphasis and hierarchical arrangement (for discussion of the various systems, see Rosatti, 1989). Bruyns & Forster (1991) have summarized this information and their system has found wide acceptance. They recognize three subfamilies, Periplocoideae, Secamonoideae and Asclepiadoideae. The former two subfamilies comprise one tribe each, the Asclepiadoideae four: Asclepiadeae, Gonolobeae, Marsdenieae and Stapelieae. A fifth tribe of the Asclepiadoideae, the Fockeeae, is presently being delimited (Kunze & al., 1994). These tribes are at least well-circumscribed and easily identifiable taxonomic units, and, in most cases, also most likely monophyletic systematic units (Liede, unpubl.). The monophyly of the Secamoneae has recently been questioned (Klackenberg, 1992), but no better concept has been proposed. The exclusion of the Fockeeae has helped to reduce considerably the heterogeneity of the Marsdenieae; however, the monophyly of the remaining taxa still needs confirmation.
50 citations
TL;DR: It is concluded that there have been many inaccurate counts but that 2n = 86-92 appears to be general and that the tribe Durioneae is distant from the remainder of the family, as also suggested by morphological, biogeographic and molecular data.
Abstract: Summary Baum, D. A. & Oginuma, K.: A review of chromosome numbers in Bombacaceae with new counts for Adansonia. - Taxon 43: 11-20. 1994. - ISSN 0040-0262. New chromosome counts are reported for all eight species of Adansonia. The six Malagasy species and the Australian species have 2n = 88, whereas the single African species, A. digitata, has 2n = 160. We review published counts for the family as a whole and conclude that there have been many inaccurate counts but that 2n = 86-92 appears to be general. A. digitata, Rhodognaphalon brevicuspe and Eriotheca pubescens are inferred to be polyploids. The tribe Durioneae, with counts of 2n = 28 and 2n = 56, is distant from the remainder of the family, as also suggested by morphological, biogeographic and molecular data.
TL;DR: The present anlysis supports the removal of Fockea from the Marsdenieae and the creation of a new tribe, Fockeeae, containing the two genera FOCkea and Cibirhiza.
Abstract: In the course of a long-term study of African Cynanchinae, several specimens of a remarkable, undetermined asclepiad from E. Africa were found in the Kew Herbarium (K). Its pollinarium structure shows strong similarity with that of Cibirhiza dhofarensis Bruyns and Fockea Endl. specimens. Anther morphology and basic corona structure agree with that of Cibirhiza, a genus established recently by Bruyns (1988). Since some important aspects remain unclear in his description, a detailed structural analysis of C. dhofarensis was necessary. Our specimens show a striking similarity to C. dhofarensis but some marked deviations in staminal corona morphology. Therefore, it seems appropriate to describe our E. African material as a new species of the genus Cibirhiza, C. albersiana. Between Fockea and the remainder of the Marsdenieae major differences have been noted several times in the past (e.g. Kunze, 1990, 1993) but systematic consequences have not been drawn yet. Our present anlysis supports the removal of Fockea from the Marsdenieae and the creation of a new tribe, Fockeeae, containing the two genera Fockea and Cibirhiza.
TL;DR: A world-wide sample of 53 Eragrostis, 1 Diandrochloa and 2 Erag Frostiella species was examined in terms of 442 newly recorded characters, revealing significant character correlations and intrageneric species relationships.
Abstract: A world-wide sample of 53 Eragrostis, 1 Diandrochloa and 2 Eragrostiella species was examined in terms of 442 newly recorded characters. These data were stored in the DELTA system and used for generating full natural language descriptions. A selection of morphological and anatomical characters (58 and 60, respectively) were analysed through a variety of phenetic and cladistic methods, revealing significant character correlations and intrageneric species relationships. The analyses are discussed in detail. A revised description of the genus Eragrostis is presented, and two subgenera are recognized, and fully described.
TL;DR: The chloroplast gene encoding rbcL sequence data support the restoration of the genus Prosartes and a synonymic conspectus of Prosarte is given, and one new combination is proposed.
Abstract: A review of the morphological and karyological data relevant to the problem of the generic distinctness of Disporum and Prosartes is presented. The chloroplast gene encoding rbcL for two species of each Disporum and Prosartes plus one of each Uvularia, Streptopus and Tricyrtis was sequenced. The data clearly separate two genera Prosartes (N. America) and Disporum (E. Asia) that were traditionally combined under the latter name. There is much more divergence between Disporum and Prosartes than between each pair of their component species, and considerably more than between Disporum and Uvularia or between Prosartes and Streptopus. The rbcL sequence data thus support the restoration of the genus Prosartes. A synonymic conspectus of Prosartes is given, and one new combination is proposed.
TL;DR: The new tribe Moquinieae is established, and scanning electron micrographs of pollen are presented of Hoplophyllum of the Eremothamneae, Gundelia of the Gundelieae, and Pseudostifftia of the Moquiniesae, with comparisons of their pollen.
Abstract: Summary Robinson, H.: Notes on the tribes Eremothamneae, Gundelieae, and Moquinieae, with comparisons of their pollen. - Taxon 43: 33-44. 1994. - ISSN 0040-0262. The new tribe Moquinieae is established, and scanning electron micrographs of pollen are presented of Hoplophyllum of the Eremothamneae, Gundelia of the Gundelieae, and Pseudostifftia of the Moquinieae. For most of a hundred years the number of recognized tribes in the Asteraceae remained rather constant as defined by Bentham (in Bentham & Hooker, 1873). Bentham accepted only thirteen tribes: Vernonieae, Eupatorieae, Astereae, Inulae, Heliantheae, Helenieae, Anthemideae, Senecioneae, Calenduleae, Arctotideae, Cynareae, Mutisieae, and Cichorieae. Of these, only the Helenieae were described as new by Bentham. Some additional tribes recognized by Cassini (Solbrig, 1963) were placed in the synonymy of the Senecioneae, Cynareae, and Mutisieae by Bentham. In spite of numerous errors of delimitation, the Bentham concepts were maintained by Hoffmann (1890-1894) and in the review of the Asteraceae by Cronquist (1955), and they were the working basis for the symposium on the family edited by Heywood & al. (1977). Twentieth Century corrections on the Bentham concepts include the transfer of Ursinia Gaertn. from the Arctoteae to the Anthemideae (Beauverd, 1915). The latter position is accepted today in spite of a difference in the pollen on which a new tribe Ursinieae (Robinson & Brettell, 1973b) was based. The value of the Helenieae was considered dubious by many authors (Cronquist, 1955), but Stuessy (1977) was the first since Bentham to place Helenium L. in the Heliantheae. Robinson (1981) subsequently treated the Helenieae and many genera from the Senecioneae as members of the Heliantheae. Descriptions of new tribes after Bentham & Hooker (1873) started with Rydberg's Adenocauleae (Rydberg, 1917), which are tentatively accepted here; Iveae (Rydberg, 1917), now placed in the Heliantheae, subtribe Ambrosiinae; Liabeae (Rydberg, 1927), redescribed and accepted by Robinson & Brettell (1973a, 1974) and Robinson & Marticorena (1986); Neurolaeneae (Rydberg, 1927), now placed in the Heliantheae; and Ursineae (Robinson & Brettell, 1973b, now placed in the Anthemideae. The Eremothamneae, described by Robinson & Brettell (1973c), have been recently reviewed and expanded (Karis, 1992; Robinson, 1992). The Gnaphalieae, named by Bentham (1867), but included in the Inuleae in Bentham & Hooker (1873), were renamed by Rydberg (1917), and are now accepted by Anderberg (1991a). Strother (1977) resurrected the Tageteae Cass. In the same symposium, Turner & Powell (1977) named the tribe Coreopsideae, emphasizing cytochrome C differences between Guizotia Cass., traditionally placed in the subtribe Coreopsidinae, and Helianthus L.
TL;DR: Anatomical evidences suggest that Sanango is most closely related to the Scrophulariales, sharing many important features with the Gesneriaceae.
Abstract: Summary was undertaken in an attempt to help clarify the relationships of the genus. Detailed descriptions of leaf, stem, nodal, wood, and floral anatomy are presented. Wood is characterized by a combination of solitary and grouped vessels with elements having few-barred scalariform perforation plates, imperforate tracheary elements with very reduced pit borders, exceptionally tall and broad hetero- cellular rays, and vasicentric axial parenchyma. Of special interest is the presence in Sanango of a very uncommon multilacunar nodal structure having split-lateral traces. Stems possess cortical vascular bundles. Leaf stomata are anisocytic and distributed in clusters on the undersurface of the lamina. Anatomical evidences suggest that Sanango is most closely related to the Scrophulariales, sharing many important features with the Gesneriaceae.
TL;DR: The United States Potato Introduction Station Herbarium at Sturgeon Bay, Wisconsin, serves the National Research Support Program-6 (NRSP-6; formerly known as the Inter-Regional Potato Introduction Project IR-1) as mentioned in this paper.
Abstract: The United States Potato Introduction Station Herbarium at Sturgeon Bay, Wisconsin, serves the National Research Support Program-6 (NRSP-6; formerly known as the Inter-Regional Potato Introduction Project IR-1). NRSP-6 is part of the US germplasm system and is the sole gene bank for wild and cultivated potatoes in the USA. The gene bank and herbarium are devoted entirely to wild and cultivated potatoes (Solanum sect. Petota). NRSP-6 is charged with the introduction, preservation, classification, evaluation and distribution of potato germplasm worldwide. Recent expeditions and grants for upgrading the herbarium and associated facilities have provided a valuable new international resource for researchers in sect. Petota.
TL;DR: The recent exchange between Rodrigo and Baum & Ragan (1993) highlights several current controversies, and it would appear that both approaches seek to maximize "evidence", one derived directly from data derived from characters, the other from the relationships those data imply.
Abstract: The recent exchange between Rodrigo (1993) and Baum & Ragan (1993) highlights several current controversies. Rodrigo (1993) made several points concerning Baum's (1992) paper (and, by implication, Ragan, 1992a, b) on combining trees to reach a solution concerning hypotheses from differing datasets. I believe many of Rodrigo's comments are misplaced, both over how he perceives the problem and how he sees Baum & Ragan's (1993) proposed solution. The ideas expressed by both sets of authors impinge on the broader debate over the use of taxonomic congruence or character congruence in generating the most efficient summary of all available data to hand. The debate can be summarized as follows. Kluge (1989) made several assertions concerning what he believed to be "conflicting" approaches in phylogenetic inference when faced with data-sets from different sources (e.g. morphology, fossils, DNA, etc.). The apparent conflict is between character congruence ("total evidence", e.g. Kluge, 1989) and taxonomic congruence (consensus, e.g. Nelson, 1979). In another paper, Jones & al. (1993: 93) defined total evidence as "... the analysis of an unpartitioned body of evidence, ideally all the data available for a group of terminal taxa" that is characterised as "seek[ing] a single, best-fitting hypothesis, which in cladistics involves maximising character congruence". The competing approach, taxonomic congruence, "seeks a consensus of hypotheses obtained from different data sets ...". This approach is characterized by three steps: (1) "evidence is partitioned into 'different types of data' " (Shaffer & al., 1991: 284), (2) "hypotheses of relationships, i.e. fundamental cladograms, are obtained from each data set", and (3) "a consensus of those topologies is constructed" (Jones & al., 1993: 93). Following the characterization given above, it would appear that both approaches seek to maximize "evidence", one derived directly from data derived from characters, the other from the relationships (cladograms) those data imply. The issue can be seen more precisely as identifying the nature of "evidence". This could be answered (albeit simplistically) by stating that, in the total evidence approach, data (direct observations into characters) are taken as evidence, while the taxonomic congruence approach uses as evidence summaries of partitioned data (cladograms). The methods of Baum (1992) and Ragan (1992a, b; cf. Baum & Ragan, 1993) fall into the second category. Given two data-sets, each may suggest differing relationships among the taxa studied. Should the data-sets be combined into one analysis, or should the cladograms derived from each data-set be combined? Rodrigo suggested that, "... given two incompatible hypotheses ... there are two ways of choosing between [them] ... (1): design a critical experiment such that the experiment will
TL;DR: A study of morphological and alkaloid variation indicates that the two genera run much into one another, and the unique combination of major alkaloids occurring in both genera suggests that they are congeneric.
Abstract: The generic delimitation of Liparia L. and Priestleya DC. (Fabaceae, tribe Liparieae) is reevaluated. Traditionally the shape and size of the carinal lobe of the calyx, the shape of the keel petals and the number of flowers per inflorescence were used as diagnostic characters. A study of morphological and alkaloid variation indicates that the two genera run much into one another. Differences in inflorescence and floral structure can be attributed to adaptations to different pollination strategies. The unique combination of major alkaloids occurring in both genera also suggests that they are congeneric. Priestleya is therefore placed into synonymy under Liparia. The nomenclature, synonymy and typification of the genus and the 14 species recognized are presented, and some necessary new combinations are made.