The pollination ecology of buzz-pollinated Rhexia virginica (Melastomataceae).

abstract：:Seeds are useful in distinguishing among extant genera of Vitaceae and provide a good basis for interpretation of fossil remains in reconstructing the evolutionary and phytogeographic history of this putatively basal Rosid family. Seeds of Ampelocissus s.l. including Pterisanthes and Nothocissus are distinguished from...

journal_title：American journal of botany

authors： Chen I,Manchester SR

更新日期：2007-09-01 00:00:00

abstract：UNLABELLED: PREMISE OF THE STUDY:An anatomical examination of dry and fleshy fruits within the Solanaceae was carried out to identify comparable stages throughout development as well as features exclusive to each type of fruit. We studied fruit development of Nicotiana and Petunia, which have the plesiomorphic capsula...

journal_title：American journal of botany

authors： Pabón-Mora N,Litt A

更新日期：2011-09-01 00:00:00

abstract：:Phloem, as a major tissue mediating long-distance communication, has been an object of extensive research ever since its structure was first reported in 1837. Functional phloem consists of sieve elements (SEs) and companion cells (CCs). While SEs are enucleated conducting cells in the phloem, CCs are cells with intact...

journal_title：American journal of botany

authors： Heo JO,Roszak P,Furuta KM,Helariutta Y

更新日期：2014-09-01 00:00:00

abstract：:Understanding the role of geography and ecology in species divergence is central to the study of evolutionary diversification. We used climatic, geographic, and biological data from nine wild Andean tomato species to describe each species' ecological niche and to evaluate the likely ecological and geographical modes o...

journal_title：American journal of botany

authors： Nakazato T,Warren DL,Moyle LC

更新日期：2010-04-01 00:00:00

abstract：:Whereas the "law of the minimum" (LM) states that plant growth is limited by a single resource at any one time, the "multiple limitation hypothesis" (MLH) proposes that optimum plant behavior results from balancing resource costs and benefits so that all resources limit plant growth simultaneously. We tested the hypot...

journal_title：American journal of botany

authors： Rubio G,Zhu J,Lynch JP

更新日期：2003-01-01 00:00:00

abstract：PREMISE OF THE STUDY:A key question in evolutionary biology is why some clades are more successful by being widespread geographically, biome diverse, or species-rich. To extend understanding of how shifts in area, biomes, and pollinators impact diversification in plants, we examined the relationships of these shifts to...

journal_title：American journal of botany

authors： Kriebel R,Drew BT,Drummond CP,González-Gallegos JG,Celep F,Mahdjoub MM,Rose JP,Xiang CL,Hu GX,Walker JB,Lemmon EM,Lemmon AR,Sytsma KJ

更新日期：2019-04-01 00:00:00

abstract：:Koch et al. (Nature 428: 851-854) measured various parameters that were thought to limit the height of Sequoia sempervirens from northern California and concluded that the maximum height for this species is 122-130 m because within this range: (1) Irreversible embolism formation was proposed to occur when the xylem pr...

journal_title：American journal of botany

authors： Netting AG

更新日期：2009-02-01 00:00:00

abstract：:We tested the hypothesis that trees growing at high elevations with occasional freezing temperatures have smaller diameter xylem vessels than trees of the same species growing at lower and warmer elevations. The young branch wood of the wide-ranging Hawaiian tree species Metrosideros polymorpha (Myrtaceae) was examine...

journal_title：American journal of botany

authors： Fisher JB,Goldstein G,Jones TJ,Cordell S

更新日期：2007-05-01 00:00:00

abstract：PREMISE OF THE STUDY:Generic boundaries and infrageneric relationships among the charismatic temperate magnoliid Asarum sensu lato (Aristolochiaceae) have long been uncertain. Previous molecular phylogenetic analyses used either plastid or nuclear loci alone and varied greatly in their taxonomic implications for the ge...

journal_title：American journal of botany

authors： Sinn BT,Kelly LM,Freudenstein JV

更新日期：2015-05-01 00:00:00

abstract：PREMISE OF THE STUDY:The opuntias (nopales, prickly pears) are not only culturally, ecologically, economically, and medicinally important, but are renowned for their taxonomic difficulty due to interspecific hybridization, polyploidy, and morphological variability. Evolutionary relationships in these stem succulents ha...

journal_title：American journal of botany

authors： Majure LC,Puente R,Griffith MP,Judd WS,Soltis PS,Soltis DE

更新日期：2012-05-01 00:00:00

abstract：:Atriplex prostrata Boucher, a facultative halophyte, exhibits significant reduction in height and biomass and in the width of the cortex and vascular tissue under saline conditions. Therefore, the goal of this investigation was to determine the effect of salinity on plant growth as well as on the patterns of lignifica...

journal_title：American journal of botany

authors： Wang L,Showalter A,Ungar I

更新日期：1997-09-01 00:00:00

abstract：:The hollow stem of Equisetum giganteum owes its mechanical stability to an outer ring of strengthening tissue, which provides stiffness and strength in the longitudinal direction, but also to an inner lining of turgid parenchyma, which lends resistance to local buckling. With a height >2.5 m isolated stems are mechani...

journal_title：American journal of botany

authors： Spatz H,Köhler L,Speck T

更新日期：1998-03-01 00:00:00

abstract：:Biogeographical patterns and diversification processes in Andean and Patagonian flora are not yet well understood. Calceolaria is a highly diversified genus of these areas, representing one of the most specialized plant-pollinator systems because flowers produce nonvolatile oils, a very unusual floral reward. Phylogen...

journal_title：American journal of botany

authors： Cosacov A,Sérsic AN,Sosa V,De-Nova JA,Nylinder S,Cocucci AA

更新日期：2009-12-01 00:00:00

abstract：:Although theory has demonstrated rather low levels of gene flow are sufficient to counteract opposing mutation, drift, and selection, widespread recognition of the evolutionary importance of gene flow has come slowly. The perceived role of gene flow as an evolutionary force has vacillated over the last century. In the...

journal_title：American journal of botany

authors： Ellstrand NC

更新日期：2014-05-01 00:00:00

abstract：PREMISE OF THE STUDY:The ability of insect visitors to learn to manipulate complex flowers has important consequences for foraging efficiency and plant fitness. We investigated learning by two butterfly species, Danaus erippus and Heliconius erato, as they foraged on the complex flowers of Asclepias curassavica, as wel...

journal_title：American journal of botany

authors： Ramos BCM,Rodríguez-Gironés MA,Rodrigues D

更新日期：2017-08-01 00:00:00

abstract：:Sex allocation models predict that cosexuality is stabilized by high allocation to attractive structures in pollen-limited species or by high allocation to shared structures that contribute to both genders. High investment in unilateral fixed costs favor the evolution of dioecy or gender change. With these predictions...

journal_title：American journal of botany

authors： Méndez M

更新日期：2001-10-01 00:00:00

abstract：:Reproductive traits of tropical tree species vary predictably in relation to successional stage, but this variation may be due to the species' phylogenetic histories rather than selective pressures imposed by regeneration requirements. Reproductive phenology, tree size at the onset of reproduction, and fecundity of 11...

journal_title：American journal of botany

authors： Davies SJ,Ashton PS

更新日期：1999-12-01 00:00:00

abstract：:Taxonomical classification of higher fungi remains an important challenge and can benefit from the application of molecular analysis. We propose that the ectomycorrhizal (EM) fungal taxa might include a number of cryptic species because there are few morphological characteristics useful for distinguishing among these ...

journal_title：American journal of botany

authors： Sato H,Yumoto T,Murakami N

更新日期：2007-10-01 00:00:00

abstract：:The phenotype of maize plants that are homozygous recessive for the nuclear gene iojap is commonly an "anemic," grainy green appearance accompanied by white leaf stripes, white leaf margins, and reduced growth. In plants in which the iojap effect is occurring (homozygous ij/ij), we find affected tissue varies in exten...

journal_title：American journal of botany

authors： Coe EH Jr,Thompson D,Walbot V

更新日期：1988-05-01 00:00:00

abstract：:The desert moss Syntrichia caninervis exhibits one of the most skewed sex ratios in the plant kingdom, with female individuals far outnumbering male individuals (exceeding 14♀:1♂). The "cost of sex hypothesis" derives from allocational theory and predicts that the sex which is most expensive should be the rarer sex. T...

journal_title：American journal of botany

authors： Stark LR,Mishler BD,McLetchie DN

更新日期：2000-11-01 00:00:00

abstract：PREMISE OF THE STUDY:Many ecological and evolutionary processes shape the assembly of organisms into local communities from a regional pool of species. We analyzed phylogenetic and functional diversity to understand community assembly of the ferns of Florida at two spatial scales. METHODS:We built a phylogeny for 125 ...

journal_title：American journal of botany

authors： Sessa EB,Chambers SM,Li D,Trotta L,Endara L,Burleigh JG,Baiser B

更新日期：2018-03-01 00:00:00

abstract：UNLABELLED: PREMISE OF THE STUDY:Verbenaceae consist of trees, shrubs, lianas, and herbs distributed primarily in Latin America, where they occur in a wide array of ecosystems. A second center of diversity exists in Africa. Competing morphology-based classifications that rely on different traits conflict in significan...

journal_title：American journal of botany

authors： Marx HE,O'Leary N,Yuan YW,Lu-Irving P,Tank DC,Múlgura ME,Olmstead RG

更新日期：2010-10-01 00:00:00

abstract：:In a 3-yr study, we examined the pollinator guild and intersexual floral characteristics of the dioecious, perennial cloudberry (Rubus chamaemorus), which flowers in early spring. The findings contribute to our general understanding of pollination ecology at high latitudes and provide important information for the com...

journal_title：American journal of botany

authors： Brown AO,McNeil JN

更新日期：2009-06-01 00:00:00

abstract：:For more than a century, the common ancestor of flowering plants was thought to have had a seven-celled, eight-nucleate Polygonum-type female gametophyte. It is now evident that not one, but in fact three, patterns of female gametophyte development and mature structure characterize the common ancestors of the four mos...

journal_title：American journal of botany

authors： Friedman WE,Ryerson KC

更新日期：2009-01-01 00:00:00

abstract：:Evolutionary relationships among representatives of Apiaceae (Umbelliferae) subfamily Apioideae have been inferred from phylogenetic analyses of nuclear ribosomal DNA internal transcribed spacer (ITS 1 and ITS 2) and plastid rpoC1 intron sequences. High levels of nucleotide sequence variation preclude the use of the I...

journal_title：American journal of botany

authors： Downie S,Ramanath S,Katz-Downie D,Llanas E

更新日期：1998-04-01 00:00:00

abstract：:We propose a new method, the leaf measuring-interval index (LMI), to estimate leaf age in morphological and physiological studies of leaves. When the plastochron, the interval between the initiation of successive leaves, is constant, the well-known leaf plastochron index (LPI) provides a robust measure of leaf age. Wh...

journal_title：American journal of botany

authors： Chen CC,Chen H,Chen YR

更新日期：2009-07-01 00:00:00

abstract：PREMISE OF THE STUDY:Anatomical and morphological features of Satanocrater were studied to test hypotheses of xeric adaptations in the genus, which is endemic to arid tropical Africa. These features, together with molecular data, were used to test the phylogenetic placement of Satanocrater within the large plant family...

journal_title：American journal of botany

authors： Tripp EA,Fatimah S

更新日期：2012-06-01 00:00:00

abstract：PREMISE OF THE STUDY:Subtribe Hakeinae (526 spp.) represents a large Australian plant radiation central to our understanding of that flora's evolution and ecology. It contains Grevillea-the third largest plant genus in Australia and a group inferred to have among the highest diversification rates in the angiosperms. Ho...

journal_title：American journal of botany

authors： Mast AR,Olde PM,Makinson RO,Jones E,Kubes A,Miller ET,Weston PH

更新日期：2015-10-01 00:00:00

abstract：:Recent discoveries of fossil reproductive structures from deposits of the Raritan Formation in New Jersey (Turonian, Upper Cretaceous, ~90 million years BP) include a previously undescribed representative of the Order Capparales. The fossils are usually charcoalified with three-dimensional structure and excellent anat...

journal_title：American journal of botany

authors： Gandolfo M,Nixon K,Crepet W

更新日期：1998-07-01 00:00:00

abstract：UNLABELLED: PREMISE OF THE STUDY:The role of hybridization in plant evolution remains a source of intense debate. Potential consequences range from genetic dead-ends to species fusion or hybrid speciation. While much has been learned from model systems such as Populus, Iris, and Helianthus, many questions remain. Cons...

journal_title：American journal of botany

authors： Furches MS,Small RL,Furches A

更新日期：2013-10-01 00:00:00