Cobbania corrugata gen. et comb. nov. (Araceae): a floating aquatic monocot from the Upper Cretaceous of western North America.

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：:We investigated patterns of fruit and seed production on inflorescences of a population of Pancratium maritimum in northwest Spain over a 2-yr period. Initial findings showed that the earliest opening flowers on an inflorescence are more likely to set fruit and produce more seeds than later opening flowers and that th...

journal_title：American journal of botany

authors： Medrano M,Guitián P,Guitián J

更新日期：2000-04-01 00:00:00

abstract：UNLABELLED: PREMISE OF THE STUDY:The Malpighiaceae include ∼1300 tropical flowering plant species in which generic definitions and intergeneric relationships have long been problematic. The goals of our study were to resolve relationships among the 11 generic segregates from the New World genus Mascagnia, test the mon...

journal_title：American journal of botany

authors： Davis CC,Anderson WR

更新日期：2010-12-01 00:00:00

abstract：:Zeuxine gracilis, Zeuxine strateumatica, and Eulophia sinensis are wild orchids with different breeding systems and colonizing abilities. Zeuxine gracilis is an outcrosser with restricted distribution, whereas S. strateumatica is an apomictic colonizer found only in newly available open habitats. Eulophia sinensis is ...

journal_title：American journal of botany

authors： Sun M,Wong KC

更新日期：2001-12-01 00:00:00

abstract：:Many plant species contain populations with more than one polyploid cytotype, but little is known of the mechanisms maintaining several cytotypes in a population. Andropogon gerardii cytotypes were compared to evaluate different models of autopolyploid cytotype coexistence. The enneaploid (90 chromosome, 9x) cytotype ...

journal_title：American journal of botany

authors： Keeler KH,Davis GA

更新日期：1999-07-01 00:00:00

abstract：PREMISE OF THE STUDY:The evolutionary shift from radial to bilateral symmetry in flowers is generally associated with the evolution of low flower-size variation. This phenomenon supports the hypothesis that the lower size variation in bilateral flowers can be attributed to low pollinator diversity. In this study, we pr...

journal_title：American journal of botany

authors： Nikkeshi A,Kurimoto D,Ushimaru A

更新日期：2015-12-01 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：:We examined the effects of size and spatial isolation of fens on the isozyme variability of 17 populations of Swertia perennis. This long-lived perennial is a locally abundant fen specialist in Switzerland, where wetlands have been strongly fragmented. Isozyme variability was comparable to other outcrossing plants (A ...

journal_title：American journal of botany

authors： Lienert J,Fischer M,Schneller J,Diemer M

更新日期：2002-05-01 00:00:00

abstract：UNLABELLED: PREMISE OF THE STUDY:Vessels are the chief conduit for long-distance water transport in the majority of flowering plants. Vessel length is a key trait that determines plant hydraulic efficiency and safety, yet relatively little is known about this xylem feature. • METHODS:We used previously published stud...

journal_title：American journal of botany

authors： Jacobsen AL,Pratt RB,Tobin MF,Hacke UG,Ewers FW

更新日期：2012-10-01 00:00:00

abstract：:Seed and pollen morphology were studied by light microscopy and scanning electron microscopy in 39 North and Central American species of Houstonia (including Hedyotis, but excluding Oldenlandia). Chromosome counts were obtained for eight taxa, of which five lacked previous chromosome data. A chromosome number of n = 1...

journal_title：American journal of botany

authors： Terrell EE,Lewis WH,Robinson H,Nowicke JW

更新日期：1986-01-01 00:00:00

abstract：:Multicellularity has evolved at least once in every major eukaryotic clade (in all ploidy levels) and numerous times among the prokaryotes. According to a standard multilevel selection (MLS) model, in each case, the evolution of multicellularity required the acquisition of cell-cell adhesion, communication, cooperatio...

journal_title：American journal of botany

authors： Niklas KJ

更新日期：2014-01-01 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：: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：PREMISE OF THE STUDY:Studies of natural genetic variation can elucidate the genetic basis of phenotypic variation and the past population structure of species. Our study species, Taxodium distichum, is a unique conifer that inhabits the flood plains and swamps of North America. Morphological and ecological differences ...

journal_title：American journal of botany

authors： Ikezaki Y,Suyama Y,Middleton BA,Tsumura Y,Teshima K,Tachida H,Kusumi J

更新日期：2016-11-01 00:00:00

abstract：PREMISE OF THE STUDY:Astragalus sect. Humillimi is distributed across the southwestern United States and contains two endangered taxa, A. cremnophylax var. cremnophylax and A. humillimus. The former was originally described from the South Rim of the Grand Canyon. Analysis of individuals discovered on the North Rim of t...

journal_title：American journal of botany

authors： Massatti R,Belus MT,Dowlatshahi S,Allan GJ

更新日期：2018-10-01 00:00:00

abstract：:In monocarpic plants, reproduction is closely associated with senescence, which is itself often correlated to specific environmental signals. Floerkea proserpinacoides (Limnanthaceae) is a spring ephemeral annual of the deciduous forests of eastern North America. The phenology of its growth and reproduction is conside...

journal_title：American journal of botany

authors： Mokhtar IB,Houle G

更新日期：2005-03-01 00:00:00

abstract：:Microscopic structures (petrofilaments) may develop during palynological laboratory processing procedures that are superficially similar to secondary wall thickenings and elaters. These filaments form from angular bodies that resemble fungal spores and resin bodies. The angular bodies are a type of hydrocarbon called ...

journal_title：American journal of botany

authors： Graham A,Wood GD,Elsik WC,Speed RC

更新日期：2000-05-01 00:00:00

abstract：PREMISE OF THE STUDY:Identifying recently diverged taxa can be useful for studying the process of speciation. Ipomoea lacunosa and I. cordatotriloba, along with a putative homoploid hybrid, I. ×leucantha, are closely related taxa, which are promising for investigating the early stages of speciation. The objectives of t...

journal_title：American journal of botany

authors： Duncan TM,Rausher MD

更新日期：2013-11-01 00:00:00

abstract：:The ultrastructure of Typha latifolia pollen was examined as a function of pollen moisture content and incubation temperature, in order to identify possible lesions induced by imbibitional chilling. A syndrome of structural traits was found which characterizes damaged grains. Compared to viable grains, the protoplas...

journal_title：American journal of botany

authors： Sack FD,Leopold AC,Hoekstra FA

更新日期：1988-01-01 00:00:00

abstract：PREMISE OF THE STUDY:Sex lability (i.e., gender diphasy) in plants is classically linked to the larger resource needs associated with the female sexual function (i.e., seed production) compared to the male function (i.e., pollen production). Sex lability in response to the environment is extensively documented in dioec...

journal_title：American journal of botany

authors： Varga S,Kytöviita MM

更新日期：2016-11-01 00:00:00

abstract：:Deciphering species relationships and hybrid origins in polyploid agamic species complexes is notoriously difficult. In this study of cheilanthoid ferns, we demonstrate increased resolving power for clarifying the origins of polyploid lineages by integrating evidence from a diverse selection of biosystematic methods. ...

journal_title：American journal of botany

authors： Grusz AL,Windham MD,Pryer KM

更新日期：2009-09-01 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：:The selective maintenance of gynodioecy depends on the relative fitness of the male-sterile (female) and hermaphroditic morphs. Females may compensate for their loss of male fitness by reallocating resources from male function (pollen production and pollinator attraction) to female function (seeds and fruits), thus in...

journal_title：American journal of botany

authors： Williams CF,Kuchenreuther MA,Drew A

更新日期：2000-05-01 00:00:00

abstract：PREMISE OF THE STUDY:Seed cone scales assigned to the genus Schizolepidopsis are widespread in Late Triassic to Cretaceous Eurasian deposits. They have been linked to the conifer family Pinaceae based on associated vegetative remains, but their exact affinities are uncertain. Recently discovered material from the Early...

journal_title：American journal of botany

authors： Leslie AB,Glasspool I,Herendeen PS,Ichinnorov N,Knopf P,Takahashi M,Crane PR

更新日期：2013-12-01 00:00:00

abstract：UNLABELLED:• PREMISE OF THE STUDY:Polymorphic microsatellite primers were developed in the seagrass Halophila ovalis to investigate genetic variation. • METHODS AND RESULTS:Ten polymorphic microsatellite loci were developed in Halophila ovalis. The number of alleles per locus ranged from 2 to 12 across 80 H. ovalis i...

journal_title：American journal of botany

authors： Xu NN,Yu S,Zhang JG,Tsang PK,Chen XY

更新日期：2010-06-01 00:00:00

abstract：:It is generally thought that sedimenting plastids are responsible for gravity sensing in higher plants. We directly tested the model generated by the current statolith hypothesis that the gravity sensing that leads to gravitropism results from an interaction between the plastids and actin microfilaments. We find that ...

journal_title：American journal of botany

authors： Staves MP,Wayne R,Leopold AC

更新日期：1997-11-01 00:00:00

abstract：:The fresh weights of suspension cultures of pear (Pyrus communis) and quince (Cydonia oblonga) increased exponentially for 30 to 40 days after subculturing. Transferring pear cultures to media in which quince cultures had grown for 10 days resulted in a 70% inhibition of callus growth. Transferring quince cultures to ...

journal_title：American journal of botany

authors： Moore R

更新日期：1986-01-01 00:00:00

abstract：PREMISE OF THE STUDY:Phenological mismatch has received attention in plant-pollinator interactions, but less so in seed dispersal mutualisms. We investigated whether the seasonal availability of myrmecochorous seeds is well matched to the seasonal activity patterns of seed-dispersing ants. METHODS:We compared seasonal...

journal_title：American journal of botany

authors： Gordon SCC,Meadley-Dunphy SA,Prior KM,Frederickson ME

更新日期：2019-01-01 00:00:00

abstract：:Nuclear and chloroplast DNA variation was assayed for two populations of Louisiana irises (Bayou Teche and Young's Coulee) that demonstrated extreme morphological variation and for a sample of the putative hybrid species, Iris nelsonii. The genetic markers examined in this analysis were diagnostic for either Iris fulv...

journal_title：American journal of botany

authors： Arnold ML

更新日期：1993-05-01 00:00:00

abstract：:The recent consensus that Amborellaceae, Nymphaeales, and Austrobaileyales form the three earliest-diverging lineages of angiosperms has led comparative biologists to reconsider the origin and early developmental evolution of the angiosperm seven-celled/eight-nucleate (Polygonum-type) female gametophyte. Illicium mexi...

journal_title：American journal of botany

authors： Williams JH,Friedman WE

更新日期：2004-03-01 00:00:00