Number Of Stamens Research Articles

СРАВНИТЕЛЬНЫЙ АНАЛИЗ МОРФОМЕТРИЧЕСКИХ ПОКАЗАТЕЛЕЙ СТЕРЛЯДИ ЗИМОВАЛЬНЫХ ЯМ НИЖНЕГО ИРТЫША

The article describes the results of morphometric studies of sterlet caught in water areas of two riverbed depressions of the Lower Irtysh (the Tyumen region) The studies were carried out in the period from 2015-2018, the riverbed depressions were remote from each other: Gornoslinkinskaya (the Uvat region), Kondinskaya (the Khanty-Mansiysk region). The geographic distance (the distance between the riverbed depressions is 445 km) and short migration length (about 200 km) prompted the assumption about the probability of significant discrepancies in the signs that suggest the allocation of any subgroups of sterlet. In the catches of sterlet in the Kondinskaya riverbed depression there were 93 specimens aged 1-4 years old. In the water area of the Gornoslinkinskaya riverbed depression 128 specimens were caught at the age of 1-7 years old. The comparison of sterlet groups from remote riverbed depressions was conducted using meristic signs: the number of bone plates (scutes) rays in the fins, the number of stamens on the first gill arch. According to the research results, it has been stated that there are no significant differences in the number of dorsal, lateral and ventral bone plates. Also, no differences were found in the number of stamens on the first gill arch. The greatest differences in the studied groups of sterlet were recorded in terms of the number of rays in the dorsal and anal fins. Additionally, the meristic features have been estimated by Mayr coefficient (1971), the value of which is equal to or greater than 1.28, which suggests the subspecific division. In our study, Mayr coefficient in all cases was less than 1.28, its maximum value (0.38) was established in studying the number of stamens on the 1-st gill arch. As for the remaining signs, this value is even smaller. Thus, geographical distance (over 400 km) of sterlet groups from the 2 riverbed depressions of the Lower Irtysh should not be taken as a reason to single out any subgroup.

Morphological and Anatomical Studies on Selected Lamiaceae Medicinal Plants in Bani Matar District, Sana'a (Yemen)

Morphological and anatomical characters of stem, petiole and leaves of 16 selected medicinal taxa of family Lamiaceae collected from Bani Matar district, Sana'a (Yemen) were examined using both stereo-and light microscopes. The obtained macro-and micromorphological characters (298) were analysed using the software jmp version 13. The resulted dendrogram was discussed on the light of the current taxonomic treatments of Lamiaceae. The measurement of the quantitative characters of macro-and micromorphological characters for the studied taxa was established by multivariate analysis of variance (ANOVA). Evaluation of obtained results revealed that, many characters viz. leaf composition, stomatal types and distribution, number of stamens, stem and petiole vasculature, types of trichomes, nutlet features, number of palisade and spongy layers and types of crystals are of diagnostic value in species identification and delimitation and are potentially valuable at different taxonomic levels. All the quantitative macro- and micromorphological characters except nutlet length are highly significant in species delimitation.

Morphology and some aspects of reproductive biology of perennial buckwheat <i>Fagopyrum cymosum</i> Meissn. in the Republic of Tatarstan

Fagopyrum cymosum Meissn. is a wild perennial species of buckwheat, which grows in southwest Asia. Despite rather active economic use of perennial buckwheat, only the most general information concerning the morphology and reproductive biology of the species is found in the literature. At the same time, such information could be useful for conducting genetic-selection works. In the case of the introduction of F. cymosum into the territory of European Russia, a comprehensive study of a new species will be required. The purpose of this study is a complete morphological description, identification of flowering and nectar features, evaluation of pollen fertility and seed productivity of perennial buckwheat F. cymosum in the Republic of Tatarstan. As a result of the studies, a morphological characteristic of perennial buckwheat is given. The strong branching of shoots and flower-bearing axes of F. cymosum was revealed. It turned out that the structure of the buckwheat flower is characterized by high variability. Flowers with the highest frequency were found with the formula P₅A₈G₍₃₎ (83,3%) and P₅A₉G₍₃₎ (10,7%). Among the anomalous flowers, variants with a variable number of stamens were most often encountered. Perennial buckwheat in the Republic of Tatarstan was pollinated by wild Hymenoptera and Diptera. The sugariness of perennial buckwheat nectar compared to the selection varieties of buckwheat was insignificant, averaged 0,03 mg of sugar per flower. The fertility of pollen fluctuated within 87,596,8%, depending on the weather conditions. The real seed productivity of perennial buckwheat varied from 26,7 to 186,0 seeds per plant. As a result of the study the authors have concluded that perennial buckwheat can be grown in the conditions of the Middle Volga Region as an annual crop.

Miliusa chantaburiana (Annonaceae), a new species from SE Thailand

Miliusa chantaburiana Damthongdee & Chaowasku, a new species of Annonaceae from SE Thailand, is described and illustrated. It belongs to a clade with campanulate flowers and inner petals that are generally tightly appressed from the base to more or less the midpoint at anthesis. The new species is remarkable in possessing a strongly recurved apex of the inner petals at anthesis and can be principally differentiated from its morphologically closest species, M. pumila Chaowasku and M. filipes Ridl., both from Peninsular Thailand, by the higher number of stamens and carpels per flower and horseshoe-shaped stigmas. Miliusa chantaburiana is also unique in having a 6-base-pair insertion in the plastid matK sequence. A revised key to species in the campanulate-flowered clade in Thailand is given.Citation: Damthongdee A. & Chaowasku T. 2018: Miliusa chantaburiana (Annonaceae), a new species from SE Thailand. – Willdenowia 48: 293–301. doi: https://doi.org/10.3372/wi.48.48208Version of record first published online on 24 August 2018 ahead of inclusion in August 2018 issue.

Two new species of Tovomita (Clusiaceae) from Amazonian forest

Two new species of Tovomita from forests in western Amazonia are described. Tovomita colombiana and T. longirostrata are endemic to Colombia and Brazil, respectively. Both species have a similar number of secondary veins, stamens and carpels, but can be distinguished by floral bud shape and epicarp texture. Descriptions, illustrations and a distribution map of the species, plus a brief introduction about the taxonomic relevance of floral buds and stamen shape for the genus, are provided.

Inheritance of flower traits in ornamental pepper

Diallel crosses provide estimates of useful parameters in the selection of parents for hybridization. They also help in understanding the gene action behind the determination of characters of interest. The objective of this study was to determine the genetic control of flower traits in ornamental pepper based on a complete diallel with parents F1’s and reciprocal crosses. The experiment was conducted in a greenhouse at Laboratório de Biotecnologia Vegetal, Centro de Ciências Agrárias, Universidade Federal da Paraíba (CCA-UFPB). Seven accessions of ornamental pepper belonging to the CCA-UFPB Germplasm Bank UFPB001, UFPB004, UFPB77.3, UFPB099, UFPB134, UFPB137 and UFPB390 were used. The morphological analysis was performed on following quantitative Capsicum descriptors: days for flowering (DFL), flower diameter (FD), petal length (PL), number of petals (NP), number of stamens (NS), anther length (AL) and fillet length (FL). The data were previously submitted to analysis of variance and then to diallel analysis. All evaluated traits were adequate to the additive-dominant model. There are possibilities of genetic gains in breeding programs, for the NP, NS, AL and FL in ornamental peppers.

Phylogenomics resolves evolutionary relationships and provides insights into floral evolution in the tribe Shoreeae (Dipterocarpaceae)

A supra-annual, community-level synchronous flowering prevails in several parts of the tropical forests of Southeast Asia and its evolution has been hypothesized to be linked to pollinator shifts. The aseasonal Southeast Asian lowland rainforests are dominated by Dipterocarpaceae, which exhibit great floral diversity, a range of pollination syndromes and include species with annual and supra-annual gregarious flowering. Phylogenetic relationships within this family are still unclear, especially in the tribe Shoreeae. Here, we develop a pipeline to maximize recovery of genome-wide SNPs from restriction-site associated DNA sequencing (RADseq) in non-model organisms across wide phylogenetic scales. We then infer phylogenomic relationships in the tribe Shoreeae using both traditional and coalescent analyses. The phylogenetic trees obtained with these methods are congruent to each other and highly resolved. They allow reconstructing the evolutionary patterns of floral traits (number of stamens, anther structure and anther/appendage size) in the group. Our inferences indicate that species with many stamens, but smaller, globose anthers and longer appendages and have evolved multiple times from species with fewer stamens, but larger, oblong anthers and shorter appendages. This could have happened in parallel to iterative shifts in pollinators across the uncovered phylogeny from larger, longer generation to smaller, shorter-generation insects that can quickly build up the necessary population sizes during mass flowering episodes.

Magnolia brasiliensis (Magnoliaceae), a new species and new record for the Northeastern region of Brazil

A new species of Magnolia is described for the flora of Brazil, based on material from Bahia and Minas Gerais states. This species represents the first record of Magnoliaceae in the Northeastern region of Brazil. Magnolia brasiliensis differs from all other Brazilian species of Magnolia by having adaxially glossy leaves and differs from M. ovata by having a lower number of stamens and carpels. Despite its large extent of occurrence, the conservation status attributed to the new species is Endangered, mainly based on the low number of mature individuals in each subpopulation (< 50) and an area of occupancy of less than 16 km2.

An APETALA2 Homolog, RcAP2, Regulates the Number of Rose Petals Derived From Stamens and Response to Temperature Fluctuations.

Rosa chinensis, which is a famous traditional flower in China, is a major ornamental plant worldwide. Long-term cultivation and breeding have resulted in considerable changes in the number of rose petals, while most wild Rosaceae plants have only one whorl consisting of five petals. The petals of double flowers reportedly originate from stamens, but the underlying molecular mechanism has not been fully characterized. In this study, we observed that the number of petals of R. chinensis ‘Old Blush’ flowers increased and decreased in response to low- and high-temperature treatments, respectively, similar to previous reports. We characterized these variations in further detail and found that the number of stamens exhibited the opposite trend. We cloned an APETALA2 homolog, RcAP2. A detailed analysis of gene structure and promoter cis-acting elements as well as RcAP2 temporospatial expression patterns and responses to temperature changes suggested that RcAP2 expression may be related to the number of petals from stamen origin. The overexpression of RcAP2 in Arabidopsis thaliana transgenic plants may induce the transformation of stamens to petals, thereby increasing the number of petals. Moreover, silencing RcAP2 in ‘Old Blush’ plants decreased the number of petals. Our results may be useful for clarifying the temperature-responsive mechanism involved in petaloid stamen production, which may be relevant for the breeding of new rose varieties with enhanced flower traits.

Flower-like heads from flower-like meristems: pseudanthium development in Davidia involucrata (Nyssaceae).

Flower-like inflorescences (pseudanthia) have fascinated botanists for a long time. They are explained as condensed inflorescences implying that the pseudanthium develops from an inflorescence meristem (IM). However, recent developmental studies identified a new form of reproductive meristem, the floral unit meristem (FUM). It differs from IMs by lacking acropetal growth and shares fractionation, expansion and autonomous space filling with flower meristems (FM). The similarity among FUMs and FMs raises the question how far flower-like heads originate from flower-like meristems. In the present paper, pseudanthium development in Davidia involucrata is investigated using scanning electron microscopy. D. involucrata has pincushion-shaped heads composed of densely aggregated, perianthless flowers and associated with two large showy bracts. Early developmental stages show a huge naked FUM. The FMs appear almost simultaneously and lack subtending bracts. With ongoing FUM expansion new space is generated which is immediately used by further FM fractionation. The heads have only staminate flowers or are andromonoecious with staminate and a single perfect flower in oblique position. All FMs lack perianth structures and fractionate a variable number of stamen primordia. The perfect FM is much larger than the staminate FMs and forms a syncarpous gynoecium with inferior ovary. Pseudanthium development in D. involucrata confirms the morphogenetic similarity to FMs as to acropetal growth limitation, meristem expansion and fractionation. It thus should not be interpreted as a condensed inflorescence, but as a flower equivalent. Furthermore asthe FUM develops inside a bud, its development is considered to be influenced by mechanical pressure. The oblique position of the perfect flower, the developmental delay of the proximal flowers, and the variable number of stamens which were observed in the pseudanthium development, can be caused by mechanical pressure. Next to the Asteraceae, D. involucrata offers a further example of a pseudanthium originating from a FUM. More knowledge on FUMs is still needed to understand diversification and evolution of flower-like inflorescences.

Floral meristem size and organ number correlation in Eucryphia (Cunoniaceae).

We present a comparative flower ontogenetic study in five species of the genus Eucryphia with the aim of testing whether differences in the organ number observed can be explained by changes in the meristematic size of floral meristem and floral organs. Species native to Oceania, viz. E. milliganii, E. lucida and E. moorei, have the smallest gynoecia with ca. 6 carpels, while the Chilean E. glutinosa and E. cordifolia present more than ten carpels. E. milliganii has the smallest flower with the lowest stamen number (ca. 50), while the other species produce around 200 stamens and more. Standardized measurements of meristematic sectors were taken in 49 developing flowers that were classified into three well-defined ontogenetic stages. Sizes of meristems varied significantly among species within each developmental stage as revealed by ANOVA analyses. Significant regressions between organ number and corresponding meristem size were consistent with the premise that a larger meristem size prior to organ initiation could be determining for a higher organ number. Flower organogenesis in Eucryphia also involves relevant meristem expansion while the organs are initiated, which results in a particular androecium patterning with a chaotic stamen arrangement. Meristem expansion also appears to be slower but more extensive in species with larger initial meristematic size, suggesting that flower phenotype can be determined in ontogeny by this heterochronic interplay of space and time.

Vismia conduplicata (Hypericaceae), a new species from Mato Grosso, Brazil

Vismia conduplicata, a new species of Hypericaceae from Mato Grosso state, Brazil, is described and illustrated. It is associated to “campos de murundus”, a kind of Cerrado physiognomy with woody plants growing on earth mounds, in a grassland matrix. The species was included in Vismia sect. Trianthera, based on the number of stamens per stamen fascicle and the number of ovules per locule. A comparison with the morphologically similar species Vismia micrantha is also provided.

Diagnostics, taxonomy, nomenclature and distribution of perennial Sesuvium (Aizoaceae) in Africa.

The taxonomy of perennial Sesuvium species in Africa has been poorly investigated until now. Previously five perennial species of Sesuvium were recognised in Africa (S. congense, S. crithmoides, S. mesembryanthemoides, S. portulacastrum, and S. sesuvioides). Based on the differing number of stamens, S. ayresii is accepted here as being distinct from S. portulacastrum. Field observations in Angola also led the authors to conclude that S. crystallinum and S. mesembryanthemoides are conspecific with S. crithmoides. A new subspecies, Sesuvium portulacastrum subsp. persoonii, is described from West Africa (Cape Verde, Gambia, Guinea-Bissau, Mauritania, Senegal). The molecular phylogeny indicates the position of S. portulacastrum subsp. persoonii within the “American lineage” as a part of the Sesuvium portulacastrum complex which needs further studies. A diagnostic key and taxonomic notes are provided for the six perennial species of Sesuvium found in Africa and recognised by the authors (S. ayresii, S. congense, S. crithmoides, S. portulacastrum subsp. portulacastrum, S. portulacastrum subsp. persoonii, S. verrucosum and the facultatively short-lived S. sesuvioides). The distribution of S. crithmoides, previously considered to be endemic to Angola, is now confirmed for the seashores of Republic of Congo and DR Congo. The American species S. verrucosum is reported for the first time for Africa (the Macaronesian islands: Cape Verde and the Canaries). It is locally naturalised in Gran Canaria, being a potentially invasive species. These findings as well as new records of S. verrucosum from Asia and the Pacific Islands confirm its proneness to transcontinental introduction. Lectotypes of S. brevifolium, S. crithmoides, S. crystallinum and S. mesembryanthemoides are selected. The seed micromorphology and anatomy of the perennial African species is studied. Compared to the seeds of some annual African Sesuvium investigated earlier, those of perennial species are smooth or slightly alveolate. The aril is one-layered and parenchymatous in all species and usually tightly covers the seed. The aril detachments from the seed coat that form a white stripe near the cotyledon area easily distinguish S. verrucosum from other species under study.

Sterile stamens do not enhance seed set in females of the cryptically dioeciousThalictrum macrostylum(Ranunculaceae)

In cryptically dioecious species, at least one morph is functionally unisexual despite hermaphroditic morphology. In such species, sterile reproductive structures may indirectly increase fitness of the cryptic morph. This study manipulates pollination mode to investigate two hypotheses regarding the influence of sterile stamens on female fitness in the cryptically dioecious Thalictrum macrostylum. Pollination mode and the presence of pollen limitation in natural populations were also investigated. In two natural populations, pollen receipt on pistils was quantified in open-pollinated and pollinator-exclusion flowers with varying numbers of stamens. Seed set was quantified in additional open-pollinated flowers, a subset of which received supplemental pollen to test for pollen limitation. Females were not significantly insect pollinated at either site. Number of sterile stamens per flower was positively related to pollen receipt in open-pollinated flowers at one site, but had no influence on seed set at either site. In one population, seed set was significantly pollen limited, and high variance in seed set among pollen-addition flowers in both populations indicates that high pollen loads do not always increase seed set. In the wind-pollinated and cryptically dioecious Thalictrum macrostylum, sterile stamens in females do not appear to increase female fitness. Other explanations for the persistence of stamens and sterile pollen in females of T. macrostylum should be sought.

A new species ofCrotonL. (Euphorbiaceae) from the wet fields of Midwestern Brazil

Abstract A new species, Croton uliginosus, from Midwestern Brazil is described and illustrated. It is related to Croton junceus Baill., from which it differs mainly in shape, margins and veins of leaf blade, position of acropetiolar glands, number of pistillate flowers in the rachis, presence of glands, shape of pistillate sepals, number of stamens, and length of fruiting pistillate calyx in relation to the fruits. The habitat, preliminary conservation assessment, periods of flowering and fruiting, and morphological relationships of the novel species with its closest species are also provided. Additionally, the geographical distribution map and color plates of the new species and C. junceus are provided. The latter is a species endemic to Midwestern Brazil but not yet revealed in photographs, whose taxonomy is still poorly known.

Early eudicot reproductive structure: Fruit and flower morphology of Ranunculaecarpus Samyl. from the Early Cretaceous of eastern Siberia

AbstractFloral and fruit morphology of the early eudicot Ranunculaecarpus quinquecarpellatus Samyl. is described based on details from sectioning and microscopy of the permineralized type material from the Albian Buor-Kemyus Formation of the Zyryanka coal basin. Serial sections confirmed most of the originally described characters but revealed additional information, including hypogynous perianth and several stamens with in situ pollen. Each fruit consists of five free follicles inserted on a short receptacle. Follicles are elongate, with a dorsal keel, ventral suture and an attenuate apex, and are thin-walled, with two rows of small seeds in marginal placentation. The seeds are anatropous, ovoid, 1.3–1.7 in length, with an exotesta of cells that are rounded-hexagonal in surface view. The hypogynous perianth is composed of several free tepals. The stamens are short, with tetrasporangiate, dithecal anthers dehiscing by longitudinal slits. Pollen in situ is 18–20 mm long, 13–15 mm in equatorial diameter, with uncertain aperture configuration and a loose reticulum supported by narrow, widely spaced columellae. The combination of macromorphological characters support possible affinity to extant Ranunculaceae. However, Ranunculaecarpus is distinguished from modern members of the family by the persistence of the perianth in fruit, a smaller number of stamens (ca 10) than is typical, and pollen that is unlike that of any extant genera. Given that there are also similarities with Saxifragales, the systematic affinities of Ranunculaecarpus remain uncertain.

Floral heterochrony promotes flexibility of reproductive strategies in the morphologically homogeneous genus Eugenia (Myrtaceae).

Comparative floral ontogeny represents a valuable tool to understand angiosperm evolution. Such an approach may elucidate subtle changes in development that discretely modify floral architecture and underlie reproductive lability in groups with superficial homogeneous morphology. This study presents a comparative survey of floral development in Eugenia (Myrtaceae), one of the largest genera of angiosperms, and shows how previously undocumented ontogenetic trends help to explain the evolution of its megadiversity in contrast to its apparent flower uniformity. Using scanning electron microscopy, selected steps of the floral ontogeny of a model species (Eugenia punicifolia) are described and compared with 20 further species representing all ten major clades in the Eugenia phylogenetic tree. Additional floral trait data are contrasted for correlation analysis and character reconstructions performed against the Myrtaceae phylogenetic tree. Eugenia flowers show similar organ arrangement patterns: radially symmetrical, (most commonly) tetramerous flowers with variable numbers of stamens and ovules. Despite a similar general organization, heterochrony is evident from size differences between tissues and structures at similar developmental stages. These differences underlie variable levels of investment in protection, subtle modifications to symmetry, herkogamic effects and independent androecium and gynoecium variation, producing a wide spectrum of floral display and contributing to fluctuations in fitness. During Eugenia's bud development, the hypanthium (as defined here) is completely covered by stamen primordia, unusual in other Myrtaceae. This is the likely plesiomorphic state for Myrteae and may have represented a key evolutionary novelty in the tribe. Floral evolution in Eugenia depends on heterochronic patterns rather than changes in complexity to promote flexibility in floral strategies. The successful early establishment of Myrteae, previously mainly linked to the key innovation of fleshy fruit, may also have benefitted from changes in flower structure.

Comparative Flower and Inflorescence Organogenesis among Genera of Betulaceae: Implications for Phylogenetic Relationships

Betulaceae have simple flowers but complex inflorescences. Recent phylogenetic analyses using molecular data have produced robust phylogenetic trees of Betulaceae. In this study, we evaluated the phylogenetic value of comparative organogenetic data of reproductive organs in the context of molecular phylogenies. Flower and inflorescence developmental processes of 21 species from all six genera in Betulaceae were documented with scanning electron microscopy. In each pistillate cyme, there are one primary bract, two secondary bracts, and two or three flowers in the six genera; only in Alnus are there two tertiary bracts on the abaxial side. The pistillate flower of all genera but Alnus has tepal primordia. Two tepals stop developing early on, resulting in the lack of tepals in mature flowers of Betula; while the tepals are initiated from a common circular primordium at the base of pistil in Corylus, Ostryopsis, Carpinus, and Ostrya, and the developed tepals with irregular shape and unstable number of lobes are adnate to the top of the pistil. In staminate organogenesis, each cyme has one primary bract and three flowers in all genera; two secondary bracts are only present in Alnus, Betula, and Corylus. Staminate flowers have no tepals except in Alnus and Betula, and exhibit high variation in number of stamens among genera. The number of secondary and tertiary bracts in each pistillate and staminate cyme, as well as the presence of tepals in pistillate and staminate flowers was clarified in all genera. Micro-morphological characters were used to infer the phylogenetic relationships of genera and sections of Betulaceae. Our analyses support the division of two subfamilies: Betuloideae (Alnus and Betula) and Coryloideae (Corylus, Carpinus, Ostrya, and Ostryopsis), and three tribes: Betuleae (Alnus and Betula), Coryleae (Corylus), and Carpineae (Carpinus, Ostrya, and Ostryopsis). The results agree with those from molecular phylogenetic studies, and suggest that micro-morphological characters are phylogenetically informative in Betulaceae, and reproductive organs of Betulaceae have evolved in the direction of reduction in bracts and tepals.

Floral Development of the Endangered Genus Medusagyne (Medusagynaceae-Malpighiales): Spatial Constraints of Stamen and Carpel Increase

Premise of research. The floral development of the monotypic genus Medusagyne is investigated to understand the mechanisms of stamen and carpel increases in light of its proposed affinity with Ochnaceae.Methodology. Flowers at different stages of development were investigated with SEM.Pivotal results. Flowering shrubs are andromonoecious. Flowers arise in cymes at the end of shoots. Initiation of staminate and bisexual flowers is similar for sepals and petals, which arise in a spiral sequence. Stamen initiation is centrifugal on a broad circular primordium but becomes more or less irregular by the insertion of additional stamens between the older stamens. In staminate flowers the globular floral apex is completely covered with stamens, with no trace of carpels. Bisexual flowers emerge on the lower branches and develop a broad stamen ring surrounding a whorl of 13–16 carpels. Carpels initiate in a ring around the massive floral apex and develop mainly in a vertical direction. Carpels are progressively swamped in the stamen mass by a simultaneous expansion of filaments, and styles become irregularly compressed in older buds. The adaxial expansion of carpel tissue eventually overtops the floral apex as a roof. Measurements of buds show that carpel and stamen numbers are linked with the proportional size of the floral apex relative to the whole size of the flower bud.Conclusions. The unusual floral development of Medusagyne supports the separation of the genus in its own family, although several characters link it with the Ochnaceae clade. Stamen initiation and expansion shows much similarity with Eucryphia in Cunoniaceae. It is suggested that the larger number of carpels is intimately linked with the higher stamen numbers. Constraints of space and a vertical growth pattern of the floral apex cause the peculiar morphology of the gynoecium and the variably delayed stamen initiation.

Lack of trade-offs between the male and female sexual functions in the gynodioecious herb Geranium sylvaticum

Resource allocation trade-offs between sexual functions are predicted, but these are usually measured only at the whole plant level. In some gynodioecious species, individuals with partially restored male fertility exist providing an opportunity to investigate whether the costs associated with male fertility restoration are linked to seed production. In this study, we examined whether there is a relationship between the numbers of stamens and seeds produced both at the flower level and at the plant level in the gynodioecious herb Geranium sylvaticum. We individually marked flowers in plants varying in the degree of male sterility in the field and counted the number of seeds produced. There was no significant correlation between the numbers of stamens and seeds produced at the flower level suggesting an absence of resource trade-off between female and male functions. Furthermore, the numbers of stamens and seeds were positively correlated at the plant level. The lack of trade-offs between the two sexual functions in this species indicates that relative sex allocation was not affected by resources within a single season and/or that the male costs were relatively small.