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Female Flowers (female + flower)
Selected AbstractsComparative floral structure and systematics of Pelagodoxa and Sommieria (Arecaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2004FRED W. STAUFFER Floral structure is compared in Pelagodoxa and Sommieria (Arecaceae, Arecoideae). Male flowers have three free, imbricate sepals, three basally congenitally united and apically valvate petals, and six stamens. Anthers are dorsifixed and dehiscence introrse. The sterile gynoecium is tricarpellate. Female flowers have three free, imbricate sepals and three free, imbricate petals, which are slightly fused with the sepals at the base. Four to six staminodes are congenitally united at the base and fused with the ovary for a short distance. The gynoecium is syncarpous. Carpels are almost equal in early development; later the gynoecium becomes pseudomonomerous. The three stigmatic branches are equally developed, apical and sessile. The carpels are (syn-)ascidiate up to the level of the placenta and (sym-)plicate above. Each carpel has one ovule, in the sterile carpels it is aborted at anthesis. The fertile ovule is erect up to anthesis and pendant afterwards because of the bulging out of the ovary. Pollen tube transmitting tracts (PTTT) encompass the secretory epidermis of the ventral slits of each carpel. Floral structure in Pelagodoxa and Sommieria supports the sister group relationship between the two genera suggested in recent molecular phylogenies and reflects their close relationships to a major clade of pseudomonomerous arecoid palms from the Indo-Pacific region. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 146, 27,39. [source] Nectaries and reproductive biology of Croton sarcopetalus (Euphorbiaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2001LEANDRO FREITAS Flower morphology, nectary structure, nectar chemical composition, breeding system, floral visitors and pollination were analysed in Croton sarcopetalus, a diclinous-monoecious shrub from Argentina. Male flowers have five receptacular nectaries, with no special vascular bundles, that consist of a uniserial epidermis with stomata subtended by a secretory parenchyma. Female flowers bear two different types of nectaries: inner (IN) and outer (ON) floral nectaries. IN, five in all, are structurally similar to the nectaries of male flowers. The five ON are vascularized, stalked, and composed of secretory, column-shaped epidermal cells without stomata subtended by secretory and ground parenchyma. In addition, ON act as post-floral nectaries secreting nectar during fruit ripening. Extrafloral nectaries (EFN) are located on petioles, stipules and leaf margins. Petiolar EFN are patelliform, stalked and anatomically similar to the ON of the female flower. Nectar sampled from all nectary types is hexose dominant, except for the ON of the female flower at the post-floral stage that is sucrose dominant. The species is self-compatible, but geitonogamous fertilization is rarely possible because male and female flowers are not usually open at the same time in the same individual, i.e. there is temporal dioecism. Flowers are visited by 22 insect species, wasps being the most important group of pollinators. No significant differences were found in fruit and seed set between natural and hand pollinated flowers. This pattern indicates that fruit production in this species is not pollen/pollinator limited and is mediated by a wide array of pollinators. [source] THE EVOLUTION OF DIOECY, HETERODICHOGAMY, AND LABILE SEX EXPRESSION IN ACEREVOLUTION, Issue 11 2007S. S. Renner The northern hemisphere tree genus Acer comprises 124 species, most of them monoecious, but 13 dioecious. The monoecious species flower dichogamously, duodichogamously (male, female, male), or in some species heterodichogamously (two morphs that each produce male and female flowers but at reciprocal times). Dioecious species cannot engage in these temporal strategies. Using a phylogeny for 66 species and subspecies obtained from 6600 nucleotides of chloroplast introns, spacers, and a protein-coding gene, we address the hypothesis (Pannell and Verdú, Evolution 60: 660,673. 2006) that dioecy evolved from heterodichogamy. This hypothesis was based on phylogenetic analyses (Gleiser and Verdú, New Phytol. 165: 633,640. 2005) that included 29,39 species of Acer coded for five sexual strategies (duodichogamous monoecy, heterodichogamous androdioecy, heterodichogamous trioecy, dichogamous subdioecy, and dioecy) treated as ordered states or as a single continuous variable. When reviewing the basis for these scorings, we found errors that together with the small taxon sample, cast doubt on the earlier inferences. Based on published studies, we coded 56 species of Acer for four sexual strategies, dioecy, monoecy with dichogamous or duodichogamous flowering, monoecy with heterodichogamous flowering, or labile sex expression, in which individuals reverse their sex allocation depending on environment,phenotype interactions. Using Bayesian character mapping, we infer an average of 15 transformations, a third of them involving changes from monoecy-cum-duodichogamy to dioecy; less frequent were changes from this strategy to heterodichogamy; dioecy rarely reverts to other sexual systems. Contra the earlier inferences, we found no switches between heterodichogamy and dioecy. Unexpectedly, most of the species with labile sex expression are grouped together, suggesting that phenotypic plasticity in Acer may be a heritable sexual strategy. Because of the complex flowering phenologies, however, a concern remains that monoecy in Acer might not always be distinguishable from labile sex expression, which needs to be addressed by long-term monitoring of monoecious trees. The 13 dioecious species occur in phylogenetically disparate clades that date back to the Late Eocene and Oligocene, judging from a fossil-calibrated relaxed molecular clock. [source] Chemical ecology of obligate pollination mutualisms: testing the ,private channel' hypothesis in the Breynia,Epicephala associationNEW PHYTOLOGIST, Issue 4 2010Glenn P. Svensson Summary ,Obligate mutualisms involving actively pollinating seed predators are among the most remarkable insect,plant relationships known, yet almost nothing is known about the chemistry of pollinator attraction in these systems. The extreme species specificity observed in these mutualisms may be maintained by specific chemical compounds through ,private channels'. Here, we tested this hypothesis using the monoecious Breynia vitis-idaea and its host-specific Epicephala pollinator as a model. ,Headspace samples were collected from both male and female flowers of the host. Gas chromatography with electroantennographic detection (GC-EAD), coupled gas chromatography,mass spectrometry, and olfactometer bioassays were used to identify the floral compounds acting as the pollinator attractant. ,Male and female flowers of B. vitis-idaea produced similar sets of general floral compounds, but in different ratios, and male flowers emitted significantly more scent than female flowers. A mixture of 2-phenylethyl alcohol and 2-phenylacetonitrile, the two most abundant compounds in male flowers, was as attractive to female moths as the male flower sample, although the individual compounds were slightly less attractive when tested separately. ,Data on the floral scent signals mediating obligate mutualisms involving active pollination are still very limited. We show that system-specific chemistry is not necessary for efficient host location by exclusive pollinators in these tightly coevolved mutualisms. [source] Pollinators and Reproductive Success of the Wild Cucurbit Cucurbita maxima ssp. andreana (Cucurbitaceae)PLANT BIOLOGY, Issue 4 2001L. Ashworth Abstract: We studied the reproductive success and pollinators of Cucurbita maxima ssp. andreana in different disturbed habitats where it grows naturally. Data were obtained from three populations. One grew within a soybean crop, the other within a corn crop, and the third in an abandoned crop field. Cucurbita maxima ssp. andreana is an annual vine with a flowering period from December to April. Male flowers appear first, thereafter female and male flowers appear together. Flower lifetime (9 h) was similar in male and female flowers. The pollinator guild was comparable for the three populations but some differences in the frequency of the insect species were observed. Native bees were the main pollinators in the population in the abandoned field, while beetles pollinated the populations in crop fields. These differences were not linked with the pre-emergent reproductive success, fruit and seed set, or fruit quality. This is a self-compatible plant. Fruit and seed set and fruit traits (total mass, width and length of fruits, number of seeds per fruit, and seed mass) did not show significant differences between hand-cross and hand-self pollinated flowers. This wild cucurbit is a generalist with respect to pollinator guild, and flower visitors seem to be highly efficient in pollen transference. Cucurbita maxima ssp. andreana is well adapted to disturbed habitats because plants ripened fruits successfully, regardless of the group of insects visiting flowers. [source] Changes in Sexual Expression as Result of Defoliation and Environment in a Monoecious Shrub in Mexico: Implications for PollinationBIOTROPICA, Issue 4 2009Gerardo Arceo-Gómez ABSTRACT Folivory may indirectly impact plant reproduction through changes in sexual expression (i.e., number or proportion of male and female flowers produced), which influence plant,pollinator interactions via changes in pollinator preference or efficiency. This study is an experimental evaluation of the effect that defoliation has on sex expression in the monoecious shrub Cnidoscolus aconitifolius, how such effect varies across sites, as well as how such changes indirectly affect pollinator visitation rates. The present study used three populations of C. aconitifolius, each one located in a different site in Yucatán (México): pasture, deciduous forest and subdeciduous medium height forest and three levels of defoliation: 50 percent, 100 percent, and a control (no damage). Results showed that defoliation reduced significantly the total number of male flowers produced in two of the sites. Defoliation did not impact female flower production or the proportion of female flowers produced. Finally, floral visit rates were not affected by defoliation via changes in sexual expression and neither by site or by the interaction site × defoliation. Findings showed that defoliation had an effect on sex expression in C. aconitifolius, although apparently this change did not affect the plant,pollinator interactions. [source] Floral phenology and sex expression in functionally monoecious Rhoiptelea chiliantha (Rhoipteleaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2006SHI-GUO SUN The reproductive ecology of wind-pollinated gynomonoecious species, in which the individual plant produces both female (pistillate) and perfect flowers, has rarely been studied. We examined the floral phenology and reproductive traits in Rhoiptelea chiliantha, described as gynomonoecy, to understand the adaptive significance of this sexual system. This species is a rare tree native to south-western China and northern Vietnam. The flowers are characterized by an anemophilous pollination syndrome, but no insects were observed foraging on them. Perfect flowers have larger tepals but smaller stigmas than female flowers, indicating flower size dimorphism. Floral ratios of female to perfect flowers are stable in different individuals and populations. On individual plants, perfect flowers open first, followed by female flowers, with a 1-week interval. Perfect flowers are protogynous with a 3.7-day interval (neuter phase) between the female phase (1.5 days) and expanded male phase (8.2 days). Both female and perfect flowers exhibit pronounced synchrony in flowering at the levels of inflorescences and individuals. However, flowers on different individuals show asynchronicity in timing of initial blooming. Tracking the process from pollination to fruit maturation, we found that female flowers contributed almost exclusively to seed production, but perfect flowers were sterile (functionally males). Therefore, this plant is functionally monoecious. This finding resolved a puzzle on the occurrence of female flowers in this plant, because previous reports described female flowers as being sterile. As the sex phases were completely separate between individuals, the pattern of floral phenology may ensure that outcrossing strongly predominates. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 152, 145,151. [source] Anatomical studies on Sinofranchetia chinensis (Lardizabalaceae) and their systematic significanceBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2005XIAO-HUI ZHANG The anatomical structures of the Chinese endemic and monotypic genus Sinofranchetia (Lardizabalaceae) are described. There are reticulate, simple-reticulate, scalariform, simple-scalariform and simple perforations in vessel elements as well as in the fibres in the secondary wood of the roots and the stems. The node is trilacunar. The vascular bundles in the petiole are arranged in a ring. Clustered crystals occur in the parenchymatous cells of stems, petioles and pedicles. Leaf stomata are actinocytic. The nodes of sepals, petals and stamens both in male and female flowers are unilacunar and one-traced. There are three sterile carpels with two to three traces in the male flowers, three fertile carpels with two to three traces, and sometimes three sterile carpels lacking a vascular supply. In morphology, the anther dehiscence mechanism and pollen in the female flowers are the same as in the male flowers, such that the so-called female flowers might be bisexual in morphology. In comparing morphology, the sex of the flowers and the perforations of the vessel elements in Sinofranchetia with Decaisnea and other genera of the Lardizabalaceae, Sinofranchetia is considered a basic group at least as the same evolutionary level in the family as Decaisnea. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 149, 271,281. [source] Nectaries and reproductive biology of Croton sarcopetalus (Euphorbiaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2001LEANDRO FREITAS Flower morphology, nectary structure, nectar chemical composition, breeding system, floral visitors and pollination were analysed in Croton sarcopetalus, a diclinous-monoecious shrub from Argentina. Male flowers have five receptacular nectaries, with no special vascular bundles, that consist of a uniserial epidermis with stomata subtended by a secretory parenchyma. Female flowers bear two different types of nectaries: inner (IN) and outer (ON) floral nectaries. IN, five in all, are structurally similar to the nectaries of male flowers. The five ON are vascularized, stalked, and composed of secretory, column-shaped epidermal cells without stomata subtended by secretory and ground parenchyma. In addition, ON act as post-floral nectaries secreting nectar during fruit ripening. Extrafloral nectaries (EFN) are located on petioles, stipules and leaf margins. Petiolar EFN are patelliform, stalked and anatomically similar to the ON of the female flower. Nectar sampled from all nectary types is hexose dominant, except for the ON of the female flower at the post-floral stage that is sucrose dominant. The species is self-compatible, but geitonogamous fertilization is rarely possible because male and female flowers are not usually open at the same time in the same individual, i.e. there is temporal dioecism. Flowers are visited by 22 insect species, wasps being the most important group of pollinators. No significant differences were found in fruit and seed set between natural and hand pollinated flowers. This pattern indicates that fruit production in this species is not pollen/pollinator limited and is mediated by a wide array of pollinators. [source] Seasonal decline in male-phase duration in a protandrous plant: a response to increased mating opportunities?FUNCTIONAL ECOLOGY, Issue 4 2000R. D. Sargent Abstract 1.,We examined the effects of pollinator visitation and time of season on male- and female-phase duration, using experimental manipulation and survey data from naturally occurring populations of Chamerion (= Epilobium) angustifolium (L.) J. Holub (Onagraceae). 2.,Based on the observation that male mating opportunity (numbers of female flowers/numbers of male flowers) increases seasonally, we predicted that individual flowers should spend more time in the male phase early in the season when mating opportunity is low. We predicted that if seasonal changes in mating opportunity select for phase duration, male-phase duration should decline when pollinator effects are experimentally controlled. 3.,A comparison of phase duration in naturally pollinated and pollinator-excluded plants supported this prediction: male-phase duration in the pollinator-exclusion treatment was longer and declined faster than in the naturally pollinated group. 4.,A population survey revealed that once the effects of temperature were controlled for, male-phase duration was negatively correlated with date, while female-phase duration was positively correlated with date. 5.,These findings suggest that seasonal variation in mating opportunity, and not just pollination rate or temperature, may play a significant role in phase duration in dichogamous plants. [source] | ||||||||||