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1.
Phylogenetic analyses of nucleotide sequences of the internal transcribed spacers and 5.8 regions of the nuclear ribosomal DNA and of the trnH-psbA spacer of the chloroplast genome confirm that the three taxa of the Jacquemontia ovalifolia (Choicy) Hallier f. complex (Convolvulaceae) form a monophyletic group. Levels of nucleotide divergence and morphological differentiation among these taxa support the view that each should be recognized as distinct species. These three species display unique intercontinental disjunction, with one species endemic to Hawaii (Jacquemontia sandwicensis A. Gray.), another restricted to eastern Mexico and the Antilles [Jacquemontia obcordata (Millspaugh) House], and the third confined to East and West Africa (J. ovalifolia). The Caribbean and Hawaiian species are sister taxa and are another example of a biogeographical link between the Caribbean Basin and Polynesia. We provide a brief conservation review of the three taxa based on our collective field work and investigations; it is apparent that J. obcordata is highly threatened and declining in the Caribbean.  相似文献   

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Jacquemontia diamantinensis Buril (Convolvulaceae) described here as a new species, is endemic to the Chapada Diamantina, in Bahia, Brazil. Illustrations and a table for comparing characters with related species are provided.  相似文献   

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Chromosome numbers are reported for 128 species of flowering plants indigenous or endemic to Hawaii, including first reports for 13 genera and 82 species. The special significance of reports for Ilex, Tribulus, Keysseria, Pisonia, Boerhavia, Jacquemontia, Claoxylon, Lipochaeta, Railliardia, and Dubautia are discussed. The cytological and morphological variation in Railliardia and Dubautia is considered and their treatment as congeners is advocated. The cytogeogruphic pattern in Dubautia and Railliardia and other factors suggest that the ancestral chromosome number of the Hawaiian tarweeds is n = 14. Their derivation from a western North American progenitor similar to Adenothamnus is considered plausible if not indeed likely.  相似文献   

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Vesicular-arbuscular mycorrhizal fungi (VAMF) were a nearly constant component of the coastal strand of the Hawaiian Islands, occurring in beach sand, driftline debris, in roots of 23 of 31 species of vascular plants examined, and in association with rhizomes of two native species, Sporobolus virginicus and Jacquemontia sandwicensis. Mycorrhizae were most frequent and intensity of VAM development was greatest in endemic plants, less in indigenous species, and least in alien species. Spores of VAMF were produced in abundance between the rhizome and the leaf sheaths of Sporobolus. Roots of two strand species, including roots of Sporobolus that were immersed in seawater for 7 days, functioned as inocula of VAMF in pot-culture studies. The close association between propagules of VAMF and vegetative fragments of indigenous plants found in the present study suggests a mechanism of codispersal that appears to ensure the maintenance of the symbiosis in nutrient-deficient sites where it is most beneficial. The codispersal of fungus and plant may explain the high frequency of mycotrophy in strand species in the tropical Pacific.  相似文献   

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Taxonomic changes are made to reflect a reassessment of morphology based on the results of molecular phylogenetic studies. A new genus, Davilanthus, is described to include six species that collectively form the sister group to Simsia, and includes the following species transferred from Viguiera: Davilanthus davilae, Davilanthus hidalgoanus, Davilanthus hypargyreus, Davilanthus huajuapanus, Davilanthus purpusii, and Davilanthus sericeus. Three species formerly placed in Viguiera ser. Grammatoglossae are transferred to Simsia: Simsia benziorum, Simsia ovata, and Simsia rhombifolia.  相似文献   

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Two new species, Elaphoglossum alvaradoanum and E. pendulum, are described. The first species is endemic to Cocos Island, and the second to the mountains of Costa Rica. Elaphoglossum auripilum var. longipilosum is elevated to species rank as E. longipilosum.  相似文献   

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Our recent molecular phylogenetic study revealed a previously unrecognized clade of six species that is sister to Elaphoglossum. Within this clade, four species are currently classified in Bolbitis, one in Lomagramma, and one in Acrostichum. For this clade, we propose the name Mickelia, with M. nicotianifolia as the type species. We also make new combinations for the species in our phylogenetic study shown to belong to Mickelia (M. bernoullii, M. guianensis, M. hemiotis, M. nicotianifolia, M. oligarchica, and M. scandens) and two other species believed to belong to the clade based on morphology (M. lindigii, M. pergamentacea). A new hybrid and two new species are also described (M. ×atrans, M. furcata, and M. pradoi). In total, Mickelia consists of ten species and one hybrid. It is entirely neotropical. We provide a key to the genera of bolbitidoid ferns and a synopsis of Mickelia that gives for each species a complete synonymy, geographical distribution, comparative discussion, and illustration.  相似文献   

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Lithospermum (Boraginaceae) comprises approximately 40 species in both the Old and New Worlds, with a center of diversity in the southwestern United States and Mexico. Using ten cpDNA regions, a phylogeny of Lithospermum and related taxa was reconstructed. Lithospermum (including New World and Old World species) and related New World members of Lithospermeae form a monophyletic group, with Macromeria, Onosmodium, Nomosa, Lasiarrhenum, and Psilolaemus nested among species of Lithospermum. New World Lithospermeae also is a monophyletic group, with Eurasian species of Lithospermum sister to this group. Because Lithospermum is not monophyletic without the inclusion of the other New World genera, species from these genera are transferred to Lithospermum, and appropriate nomenclatural changes are made. New combinations are Lithospermum album, Lithospermum barbigerum, Lithospermum dodrantale, Lithospermum exsertum, Lithospermum helleri, Lithospemum leonotis, Lithospermum notatum, Lithospermum oaxacanum, Lithospermum pinetorum, Lithospermum rosei, Lithospermum trinverium, and Lithospermum unicum; new names are Lithospermum chiapense, Lithospermum johnstonii, Lithospermum macromeria, Lithospermum onosmodium, Lithospermum rzedowskii, and Lithospermum turneri.  相似文献   

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Petra Hoffmann 《Brittonia》2008,60(2):136-166
Heterosavia (Phyllanthaceae) is segregated from Savia (tribe Bridelieae), recognized at generic rank, and placed in tribe Phyllantheae. Floral, fruit, leaf anatomical, leaf venation, and pollen characters of the neotropical taxa previously united as Savia including Gonatogyne are discussed and illustrated. Keys to the three genera and to the species of Heterosavia are presented. Four species (all new combinations), Heterosavia bahamensis, H. erythroxyloides, H. laurifolia, and H. maculata, are recognized. The new combinations Heterosavia laurifolia var. intermedia and H. maculata var. clementis are proposed. The names Heterosavia, H. erythroxyloides, H. laurifolia, Savia clementis, S. clusiifolia, S. clusiifolia var. fallax, and S. longipes are lectotypified. Distribution maps and conservation assessments (IUCN ratings) of Heterosavia species and varieties are provided.  相似文献   

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A synopsis of the genus Cohniella is presented with nomenclatural updates with a discusion of diagnostic features and biogeographical data. Thirteen species and one natural hybrid are recognized. Two new species, Cohniella pendula and Cohniella biorbicularis, are described and illustrated. The following four new combinations are proposed: Cohniella binotii, Cohniella brachyphylla, Cohniella cepula, and Cohniella longifolia. Lectotypes are selected for Oncidium subulifolium, Oncidium helicanthum, Oncidium humboldtii, Oncidium jonesianum var. phaeanthum, Oncidium cepula, and Oncidium wittii. We also propose an amended lectotype for Epidendrum cebolleta and several epitypifications and new synonyms. A key to the genera of the Trichocentrum complex is presented (Appendix) as well as keys to the species of Cohniella.  相似文献   

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Polygala pauciramosa, a new species from the Federal District and the state of Goiás is described, illustrated, and compared with related species of Polygala subgenus Hebeclada. The new species is an herb that grows in seasonally to permanently wet savannas. A key to the species of Polygala subgenus Hebeclada from Goiás state, Brazil is provided.  相似文献   

15.
A new species, Allium pseudosenescens, belonging to sect. Rhizirideum (Alliaceae), is described from northeastern China. It is easily distinguished from A. senescens by the slender pedicels, pale pink perianths, narrower tepals and ovaries, yellowish anthers, and sometimes toothed subulate filaments. Also, A. senescens var. minus in sect. Rhizirideum is raised to the rank of species, as A. minus. This Korean endemic taxon is shown to be a biologically distinct species based on morphological and cytological characters. Taxonomic keys for the species of Allium sect. Rhizirideum in northeastern China and Korea are provided.  相似文献   

16.
The genus Elymus L. sensu lato includes Roegneria, Elymus, Hystrix, Sitanion and Kengyilia, and they are very important group in the tribe Triticeae. However, the phylogenetic relationships and taxonomic status of them are still in dispute. The ITS sequences were obtained and analyzed for their phylogenetic relationships by using Maximum Parsimony (MP) and Bayesian Inference (BI) methods. The main results were as follows: (1) Most species in Roegneria, Elymus and Sitanion were clustered in the St clade with diploid St genome species, and it was difficult to distinguish the species in Roegneria and Elymus; (2) The polyploid species with St genomes in the St clade were divided into three groups, which suggests that there exists differentiation of St genome in polyploids; (3) Most species of Kengyilia have only P-type of clone and clustered with diploid Agropyron species, which may suggest that Kengyilia is a valid genus; (4) Hy. patula, the type species of Hystrix was clustered with species of Elymus, while Hy. duthiei ssp. duthiei, Hy. duthiei ssp. longearistata, Hy. coreana and Hy. komarovii were grouped with diploid Psathyrostachys species. It indicated that Hy. patula is distinct related to other Hystrix species, and it is reasonable to treat Hystrix patula as Elymus hystrix and other species in Hystrix should be transferred to Leymus; (5) The “clones bias” in ITS sequences are widespread in the allopolyploid species. The article is published in the original.  相似文献   

17.
Three new hermaphrodite species of Ocotea (Lauraceae) from the campos rupestres of Brazil are described and illustrated: Ocotea pumila, which is known from Bahia state; and Ocotea colophanthera and Ocotea rupestris both from Minas Gerais state. Their diagnostic features are pointed out, and a discussion of their relationships to other species of Ocotea is provided.  相似文献   

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Essential Oils in Mexican Bays ( Litsea spp . , Lauraceae): Taxonomic Assortment and Ethnobotanical Implications. The seven species of Litsea found in Mexico, all of them popularly known as “laurel,” were surveyed by gas chromatography-mass spectrometry for their foliar essential oils composition and related ethnobotanical applications. Litsea glaucescens is in high demand as a condiment, and is sold in rural and urban markets all over Mexico. However, four other species are also locally used for food seasoning. Litsea guatemalensis is the species most used in traditional medicine, especially to treat fever, chills, infectious diseases of the digestive system, and arthritis. No reports of culinary, medicinal, or other applications were located for L. muelleri, and L. pringlei. This is the first report on the essential oils for L. neesiana, L. muelleri, L. parvifolia, L. pringlei, and L. schaffneri. The terpenoids commonly found in all the Litsea species studied were 1,8-cineole, linalool, α-pinene, β-pinene, m-cymene, terpinen-4-ol, α-terpineol, caryophyllene, and caryophyllene oxide. Nevertheless, each species can be distinguished by its characteristic assortment of terpenoids. According to hierarchical cluster analysis, three groups of species were recognized: (1) 1,8-cineole group (C-10 terpenes), consisting of L. glaucescens, L. schaffnerii, L. pringlei, and L. muelleri; (2) limonene-rich group (C-10 oxygenated terpenes), including L. guatemalensis, and L. neesiana, and (3) oxygenated sesquiterpenes-rich group (C-15 oxygenated terpenes), comprising L. parvifolia. The chemical profiles of L. glaucescens and L. guatemalensis suggest a correlation with the culinary and medicinal uses of these species due to the known properties of their main constituents.  相似文献   

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