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A synopsis of 20 species of Manihot Mill. with non-lobed or pinnately lobed leaves is presented. Six of these species were included in the section Brevipetiolatae Pax by Rogers and Appan in the latest treatment of the genus. Molecular analyses show this is not a monophyletic section, although it is useful as a practical matter to treat this as a morphologically readily delimited group. We evaluate the species previously included in section Brevipetiolatae sensu Rogers and Appan, typify names where necessary, and synonymize the section. Twenty species are clarified and six lectotypes are designated. Three species previously put into synonymy, M. brachystachys Pax & K. Hoffm., M. linearifolia Müll. Arg., and M. mattogrossensis Pax & K. Hoffm., are here resurrected, and M. graminiformis M. Mend. & T. B. Cavalc. is described as a new species. An identification key and comments on the most similar morphological species, as well as ecological aspects and distribution for each species, are included.
While it is known that whole genome duplication (WGD) and reticulate evolution play important roles in plant evolution, the origins and evolutionary histories of most polyploid and reticulate groups are still poorly known. The North Temperate haplostemonous (NTH) Ludwigia L. (sections Isnardia (L.) W. L. Wagner & Hoch, Ludwigia, Microcarpium Munz, and Miquelia P. H. Raven) group, characterized by having 4-merous and haplostemonous flowers, pluriseriate and free seeds, glabrous and convex nectaries, and a north-temperate distribution, is a polyploid complex (2×, 4×, 6×, and 8×) of 24 species with frequent reports of inter- and intrasectional hybridization. Although earlier biosystematics studies postulated some evolutionary scenarios and recent molecular phylogenetic studies have partially tested these propositions, the full history of their reticulate evolution remains puzzling. In this study, we sequenced four chloroplast regions (rpL16, rpoB-trnC, trnL-trnF, and ycf6-psbM) and conducted extensive molecular cloning of the biparentally inherited single-copy nuclear PgiC gene (376 clones in total), sampling 23 of the 24 NTH Ludwigia species whose chromosome numbers and ploidy levels were confirmed. Both the chloroplast and PgiC trees include strongly supported sister clades of section Ludwigia (four diploid species) and the “Microcarpium complex” (composed of sections Isnardia, Microcarpium, and Miquelia), which together are sister to the rest of Ludwigia. In the PgiC tree, eight clades are identified within the Microcarpium complex, with four clades including no extant diploid species. Neither sections Isnardia nor Microcarpium are monophyletic, while the monospecific section Miquelia has a hybrid origin. By integrating our phylogenetic trees with previous cytological hypotheses, the reticulate evolution of NTH Ludwigia is disentangled and four to eight extinct diploid species are inferred. Ancestral area reconstruction supports a North American origin of L. ovalis whose current East Asian distribution reflects a relict of the Arcto-Tertiary Geoflora. Based on our results, we propose to synonymize sections Microcarpium and Miquelia under the expanded section Isnardia.
Generic boundaries of the South American species Panicum longipedicellatum Swallen are explored and compared with allied genera of the tribe Paniceae. On the basis of morphological, anatomical, and molecular characters a new genus, Cnidochloa Zuloaga, is proposed. The phylogenetic position of the new genus within the Paniceae is evaluated.
Biscutella L. ser. Biscutella (= Biscutella ser. Lyratae Malin.) comprises mostly annual or short-lived perennial plants occurring in the Mediterranean basin and the Middle East, which exhibit some diagnostic floral features. Taxa in the series have considerable morphological plasticity, which is not well correlated with clear geographic or ecologic patterns. Traditional taxonomic accounts have focused on a number of vegetative and floral characters that have proved to be highly variable, a fact that contributed to taxonomic inflation mostly in northern Africa. A detailed study and re-evaluation of morphological characters, together with recent phylogenetic data based on concatenation of two plastid and one nuclear region sequence data, yielded the basis for a taxonomic reappraisal of the series. In this respect, a new comprehensive integrative taxonomic arrangement for Biscutella ser. Biscutella is presented in which 10 taxa are accepted, namely seven species and three additional varieties. The name B. eriocarpa DC. is reinterpreted and suggested to include the highest morphological variation found in northern Morocco. Its treatment here accepts two varieties, one of which is described as new (B. eriocarpa var. riphaea A. Vicente, M. Á. Alonso & M. B. Crespo). In addition, the circumscriptions of several species, such as B. boetica Boiss. & Reut., B. didyma L., B. lyrata L., and B. maritima Ten., are revisited. Nomenclatural types, synonymy, brief descriptions, cytogenetic data, conservation status, distribution maps, and identification keys are included for the accepted taxa, with seven lectotypes and one epitype being designated here.
The grass genus Poa L. is widespread throughout temperate areas of the Andes, being a common constituent in the highly diverse but threatened high-elevation páramo grasslands of northwest South America. Knowledge of Poa from these páramo areas is very limited, however, with no comprehensive taxonomic treatments available for Colombia, which contains the largest area of páramo in the Neotropics and its surrounding countries. We present a taxonomic revision of Poa for Colombia accepting 15 species, including two recent combinations of Poa previously circumscribed in Aphanelytrum (Hack.) Hack. We describe a new species, P. colombiana Soreng & Sylvester, and a new variety, P. subspicata (J. Presl) Kunth var. glabrata Soreng & Sylvester, for Colombia and Ecuador. Poa colombiana is similar to P. aequatoriensis Hack. but differs in having lemmas pubescent on the keel and marginal veins, lemma apices weakly acute, flag leaf sheath margins fused 20%–38% their length, and anthers generally larger, > 1.2 mm long. Poa subspicata var. glabrata differs from P. subspicata s. str. in having glabrous lemmas. We provide two new records for Colombia of P. huancavelicae Tovar, and P. mucuchachensis Luces. Two species, P. orthophylla Pilg. and P. reclinata (Swallen) Soreng & P. M. Peterson, are considered endemic to Colombia. Poa soderstromii Negritto & Anton is placed as a subspecies of P. orthophylla, and P. leioclada Hack. is synonymized under P. mulalensis Kunth. The names P. annua L. var. exilis Tomm. ex Freyn, P. humilis Ehrh. ex Hoffm., P. infirma Kunth, P. leioclada, P. orthophylla, P. pauciflora Roem. & Schult., P. pratensis L. subsp. irrigata (Lindm.) H. Lindb., P. puberula Steud., P. pubiflora Benth., P. subcaerulea Sm., P. subspicata, and P. trachyphylla Pilg. are lectotypified, P. mulalensis is neotypified, and P. trachyphylla is epitypified. Four species are exotic and introduced from Europe: P. annua, P. infirma, P. pratensis, and P. trivialis L. We provide a key, descriptions, illustrations, distribution and habitat information, vouchers, and notes for each species.