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1.
The taxonomic value and evolutionary significance of 30 leaf epidermal characters from 238 samples representing 127 species of all seven genera in the tribe Gaultherieae (Ericaceae) and two outgroup genera were investigated by scanning electron microscopy. The character states were coded and optimized onto a maximum‐likelihood tree based on previous molecular data with Fitch parsimony and hierarchical Bayesian analysis to trace the evolution of character states throughout all internodes in the phylogenetic tree for Gaultherieae. Leaf epidermal characters were found to be largely consistent within species, but highly variable at interspecific and higher taxonomic levels. The most recent common ancestral states of 15 characters diagnosed various lineages recovered from prior studies, some with no prior morphological support. Relatively high frequencies of state change occur in the eastern Asian clade Gaultheria series Gymnobotrys + Diplycosia, the American clade G. subsection Dasyphyta p.p., the core East Asian clade and the Australia/New Zealand clade. The characters with the highest frequencies of state change are the outer stomatal ledge ornamentation type, the stomatal apparatus level, stomatal density and area, and the type of abaxial trichomes. These character state change patterns may provide insight into the ecological adaptions of Gaultherieae during their evolutionary history. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 686–710.  相似文献   

2.
Studies on niche evolution allow us to establish how species niches have changed over time and to identify how long‐term evolutionary processes have led to present‐day species distributions. Here, we investigate the patterns of climatic niche evolution in Tynanthus (Bignonieae, Bignoniaceae), a genus of narrowly distributed species. We test the hypothesis that niche conservatism has played an important role in the history of this group of Neotropical lianas. We perform univariate and multivariate comparisons between climatic niches of species and associated environmental data with information on phylogenetic relationships. We encountered considerable divergence in niches among species, indicating that niche conservatism in climatic variables does not seem to have played a key role in the history of the genus. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 95–109.  相似文献   

3.
A survey of the three-dimensional organization of stamen vasculature in 100 genera and over 350 species of Araceae was made using clearings. The Araceae exhibit highly varied stamen vasculature, with three main patterns: 1) vascular bundles unbranched, 1–3 per stamen, 2) forked bundles in some or all stamens, 3) anastomosing vascular systems with several to many bundles entering a single stamen. Three major groups of taxa in the family can be recognized on the basis of their predominant pattern of stamen vasculature. Virtually all genera with bisexual flowers (most Pothoideae, Monsteroideae, Calloideae, Lasieae) have unbranched bundles, one per stamen, except two to three in some species of Holochlamys, Spathiphyllum, and Scindapsus. Forked stamen bundles are virtually restricted to and occur nearly throughout the monoecious Lasioideae, Philodendroideae, Colocasioideae and among certain Aroideae (sensu Engler), including tribes Arophyteae, Spathicarpeae (Asterostigmateae) and Protareae. No forked bundles were found in tribe Areae (Aroideae), except Theriophonum indicum or any Araceae with bisexual flowers, except two species of Cyrtosperma. Anastomosing systems are virtually limited to members of tribe Areae with larger stamens, such as Arum, Helicodiceros, Eminium and Dracunculus species. A similar pattern occurs in some Amorphophallus, but other patterns occur as well. The distributions of forked bundles and anastomosing systems in the family are notable because they are both highly congruent with Philodendroideae-Colocasioideae, and Aroideae, respectively, in Grayum's new system for the family. Virtually all of the genera with forked bundles are grouped together in the Philodendroideae-Colocasioideae. All of the genera with anastomosing systems are in the Areae, including the complex and variable Amorphophallus, which has an uncertain systematic placement.  相似文献   

4.
This study used pollen morphology to address taxonomic controversies related to several species belonging to subgenus Hebeclada of the genus Polygala (Polygalaceae). According to the last traditionally accepted revision of this subgenus, it comprises 40 species. Nevertheless, a recent taxonomic treatment applying more comprehensive criteria reduced this number to only nine species. Our work focused on 15 traditionally accepted species that occur in Brazil, fourteen of which have been considered as only six species in this recent taxonomic study. Pollen grains from floral buds at pre‐anthesis were collected from herbarium specimens and analysed using both visible light and scanning electron microscopy. Most of the traditionally accepted species were distinguished by different combinations of several pollen‐related features, in particular colpi number (13 or 15), pollen size and shape, and endoaperture type (endocingulate or not) and arrangement (parallel or sinuous). The species accepted in the recent taxonomic treatment could not be discriminated by pollen characters. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 609–619.  相似文献   

5.
We investigated the biogeographic history of antelope squirrels, genus Ammospermophilus, which are widely distributed across the deserts and other arid lands of western North America. We combined range‐wide sampling of all currently recognized species of Ammospermophilus with a multilocus data set to infer phylogenetic relationships. We then estimated divergence times within identified clades of Ammospermophilus using fossil‐calibrated and rate‐calibrated molecular clocks. Lastly, we explored generalized distributional changes of Ammospermophilus since the last glacial maximum using species distribution models, and assessed responses to Quaternary climate change by generating demographic parameter estimates for the three wide‐ranging clades of A. leucurus. From our phylogenetic estimates we inferred strong phylogeographic structure within Ammospermophilus and the presence of three well‐supported major clades. Initial patterns of historical divergence were coincident with dynamic alterations in the landscape of western North America, and the formation of regional deserts during the Late Miocene and Pliocene. Species distribution models and demographic parameter estimates revealed patterns of recent population expansion in response to glacial retreat. When combined with evidence from co‐distributed taxa, the historical biogeography of Ammospermophilus provides additional insight into the mechanisms that impacted diversification of arid‐adapted taxa across the arid lands of western North America. We propose species recognition of populations of the southern Baja California peninsula to best represent our current understanding of evolutionary relationships among genetic units of Ammospermophilus. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 949–967.  相似文献   

6.
Plant disjunctions have provided some of the most intriguing distribution patterns historically addressed by biogeographers. We evaluated the three hypotheses that have been postulated to explain these patterns [vicariance, stepping‐stone dispersal and long‐distance dispersal (LDD)] using Munroa, an American genus of grasses with six species and a disjunct distribution between the desert regions of North and South America. The ages of clades, cytology, ancestral characters and areas of distribution were investigated in order to establish relationships among species, to determine the time of divergence of the genus and its main lineages, and to understand further the biogeographical and evolutionary history of this genus. Bayesian inference recovered the North American M. pulchella as sister species to the rest. Molecular dating and ancestral area analyses suggest that Munroa originated in North America in the late Miocene–Pliocene (7.2 Mya; 8.2–6.5 Mya). Based on these results, we postulate that two dispersal events modelled the current distribution patterns of Munroa: the first from North to South America (7.2 Mya; 8.2–6.5 Mya) and the second (1.8 Mya; 2–0.8 Mya) from South to North America. Arid conditions of the late Miocene–Pliocene in the Neogene and Quaternary climatic oscillations in North America and South America were probably advantageous for the establishment of populations of Munroa. We did not find any relationship between ploidy and dispersal events, and our ancestral character analyses suggest that shifts associated with dispersal and seedling establishment, such as habit, reproductive system, disarticulation of rachilla, and shape and texture of the glume, have been important in these species reaching new areas. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 110–125.  相似文献   

7.
Why and how organisms differ in life‐history strategies across their range is a long‐standing topic of interest to evolutionary ecologists. Although many studies have addressed this issue for several life‐history traits, such as body size and clutch size, very few have been made for some others traits, including longevity. In the present study, we performed a comparative study aiming to develop general patterns of geographical variation in longevity of urodele and anuran amphibians using published information on demographic age derived from skeletochronology. We conducted within‐species meta‐analyses using datasets of two (ten urodele and 12 anuran species) and multiple (two urodele and nine anuran species) spatially‐separated populations and found that maturation, mean, and maximum age all increased with altitude but not with latitude in each sex of both amphibian groups. This geographical pattern held true across 33 urodele and 86 anuran species at common body sizes, independent of phylogeny. It is likely that metabolic rate, reproductive investment, and mortality risk, which are the key factors that affect longevity as suggested by ageing theory, vary systemically along altitudinal gradients but not along latitudinal gradients. The evolutionary causes behind these puzzling patterns deserve further investigation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 623–632.  相似文献   

8.
By complementing two independent systematic studies published recently on the Western Australian land snail Amplirhagada, we compare levels of morphological variation in shells and genitalia with those in the mitochondrial markers cytochrome c oxidase (COI) and 16S to evaluate the utility of mtDNA markers for delimiting species. We found that penial morphology and mitochondrial divergence are generally highly consistent in delimiting species, while shells have little overall taxonomic utility in these snails. In addition to this qualitative correspondence, there is almost no overlap between intraspecific and interspecific genetic distances in COI, with the highest intraspecific and lowest interspecific distance being 6%. This value is twice the general level suggested as a DNA barcode threshold by some authors and higher than the best average found in stylommatophoran land snails. Although in Amplirhagada land snails DNA barcoding may provide meaningful information as a first‐pass approach towards species delimitation, we argue that this is due only to specific evolutionary circumstances that facilitated a long‐termed separate evolution of mitochondrial lineages along spatial patterns. However, because in general the amounts of morphological and mitochondrial differentiation of species depend on their evolutionary history and age, the mode of speciation, distributional patterns and ecological adaptations, and absence or presence of mechanisms that prevent gene flow across species limits, the applicability of DNA barcoding has to be confirmed by morphological studies for each single group anew. Based on evidence from both molecular and morphological markers, we describe six new species from the Bonaparte Archipelago and revise the taxonomy of a further two. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 337–362.  相似文献   

9.
Tiger beetles are a remarkable group that captivates amateur entomologists, taxonomists and evolutionary biologists alike. This diverse clade of beetles comprises about 2300 currently described species found across the globe. Despite the charisma and scientific interest of this lineage, remarkably few studies have examined its phylogenetic relationships with large taxon sampling. Prior phylogenetic studies have focused on relationships within cicindeline tribes or genera, and none of the studies have included sufficient taxon sampling to conclusively examine broad species patterns across the entire subfamily. Studies that have attempted to reconstruct higher‐level relationships of Cicindelinae have yielded conflicting results. Here, we present the first taxonomically comprehensive molecular phylogeny of Cicindelinae to date, with the goal of creating a framework for future studies focusing on this important insect lineage. We utilized all available published molecular data, generating a final concatenated dataset including 328 cicindeline species, with molecular data sampled from six protein‐coding gene fragments and three ribosomal gene fragments. Our maximum‐likelihood phylogenetic inferences recover Cicindelinae as sister to the wrinkled bark beetles of the subfamily Rhysodinae. This new phylogenetic hypothesis for Cicindelinae contradicts our current understanding of tiger beetle phylogenetic relationships, with several tribes, subtribes and genera being inferred as paraphyletic. Most notably, the tribe Manticorini is recovered nested within Platychilini including the genera Amblycheila Say, Omus Eschscholtz, Picnochile Motschulsky and Platychile Macleay. The tribe Megacephalini is recovered as paraphyletic due to the placement of the monophyletic subtribe Oxycheilina as sister to Cicindelini, whereas the monophyletic Megacephalina is inferred as sister to Oxycheilina, Cicindelini and Collyridini. The tribe Collyridini is paraphyletic with the subtribes Collyridina and Tricondylina in one clade, and Ctenostomina in a second one. The tribe Cicindelini is recovered as monophyletic although several genera are inferred as para‐ or polyphyletic. Our results provide a novel phylogenetic framework to revise the classification of tiger beetles and to encourage the generation of focused molecular datasets that will permit investigation of the evolutionary history of this lineage through space and time.  相似文献   

10.
Taccarum ulei (Araceae, Spathicarpeae) is a seasonal geophytic aroid, native to north‐eastern Brazil, that flowers during two months of the rainy season. Patterns of floral thermogenesis, pollination biology, and floral traits associated with pollination syndromes were studied and compared with those of other Araceae. Two species of cyclocephaline scarabs (Scarabaeidae, Cyclocephalini) were recognized as effective pollinators: Cyclocephala celata and Cyclocephala cearae. Larvae of an unidentified species of fruit fly (Melanoloma spp., Richardiidae, Diptera) were also frequently observed in inflorescences at various maturation stages, feeding on the connectives of male florets and fruits, and thus lowering the reproductive success of individual plants. Beetles were attracted by odoriferous inflorescences in the early evening of the first day of anthesis, during the female phase. The emission of attractive volatiles was coupled with intense thermogenic activity in the entire spadix, unlike other aroids in which only certain zones of the spadix heat up. Pollen release, which marks the beginning of the male phase on the subsequent evening, was not related to floral thermogenesis. Comparative multivariate analysis of the floral traits of T. ulei points to a beetle‐pollinated aroid, although some of the observed traits of the species are not common to other taxa sharing this pollination strategy. Such incongruence might be explained by the evolutionary history of the tribe Spathicarpeae and potential pollinator shifts. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ??, ??–??.  相似文献   

11.
New species of caesalpinioid legumes, Cynometra sensu lato and Afzelia, are described from the Late Oligocene (27.23 Ma) Guang River flora in north‐western Ethiopia. Both taxa show leaf characteristics that are shared with extant species in the Guineo‐Congolian, Sudanian and/or Zambezian regions of Africa today. The presence of these two species in Ethiopia during the Palaeogene provides further evidence of the importance of the legume tribe Detarieae in northern and north‐eastern Africa throughout much of the Cenozoic, even although the clade is poorly represented in these regions today. The fossil record documents a significant palaeogeographical and evolutionary history of Detarieae in Africa, especially compared with that of Europe and Anatolia. Based on this evidence, it is unlikely that significant diversification of extant African Detarieae took place on the Eurasian landmass. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 44–54.  相似文献   

12.
Tribe Merremieae, as currently circumscribed, comprise c. 120 species classified in seven genera, the largest of which (Merremia) is morphologically heterogeneous. Previous studies, with limited sampling, have suggested that neither Merremieae nor Merremia are monophyletic. In the present study, the monophyly of Merremia and its allied genera was re‐assessed, sampling 57 species of Merremieae for the plastid matK, trnL–trnF and rps16 regions and the nuclear internal transcribed spacer (ITS) region. All genera of Merremieae and all major morphotypes in Merremia were represented. Phylogenetic analyses resolve Merremieae in a clade with Ipomoeae, Convolvuleae and Daustinia montana. Merremia is confirmed as polyphyletic and a number of well‐supported and morphologically distinct clades in Merremieae are recognized which accommodate most of the species in the tribe. These provide a framework for a generic revision of the assemblage. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015.  相似文献   

13.
This paper reviews ideas on the relationship between the ecology of clades and their distribution. Ecological biogeography represents a tradition that dates back to ancient times. It assumes that the distribution of organisms is explained by factors of present environment, especially climate. In contrast, modern systematics, following its origins in the Renaissance, concluded with Darwin that ‘neither the similarity nor the dissimilarity of the inhabitants of various regions can be accounted for by their climatal and other physical conditions’. In many cases, species distribution models – ecological niche models – based on the current environment of a species (its environmental envelope) fail to predict the actual distribution of the species. In particular, they often over‐predict distributions. In addition, a group's niche often varies in space and time. These results provide valuable evidence that Darwin was correct, and many ecologists now recognise that there is a problem with the niche theory of distribution. Current ecological processes explain distribution at smaller scales than do biogeographical and evolutionary processes, but the latter can lead to patterns that are much more local than many ecologists have assumed. Biogeographical phenomena often occur at a much smaller scale than that of the Wallacean regions. In areas that have been subjected to marine inundation or intense tectonism, many centres of endemism are only tens of kilometres across. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115 , 456–468.  相似文献   

14.
In this study, we analysed chromosome number variation and chromomycin A3/4′,6‐diamidino‐2‐phenylindole (CMA/DAPI) banding patterns in 48 species belonging to 12 genera of subtribe Pleurothallidinae (Orchidaceae) in order to understand the chromosome evolution based on recent phylogenetic hypotheses and taxonomic treatments. All species had small chromosomes, with numbers ranging from 2n = 20 in two Specklinia spp. to 2n = 80 in an unidentified Octomeria sp. In Acianthera, the most highly represented genus in this study, a great diversity of chromosome number and pattern of fluorescent bands was observed, showing heterochromatin accumulation in Acianthera section Sicariae subsection Pectinatae. Interspecific ascending and, mainly, descending dysploidy were the main mechanisms of chromosome number evolution in subtribe Pleurothallidinae. For Pleurothallidinae, x = 20 is suggested as the basic chromosome number, the same suggested for the related subtribe Laeliinae and for the whole tribe Epidendreae. The Brazilian species of the mega‐genus Stelis had chromosomes with small amounts of heterochromatin and chromosome numbers based on x2 = 16. These are generally divergent from those reported for Andean and Meso‐American species, but in agreement with the monophyletic hypothesis proposed for Stelis spp. with a Brazilian Atlantic distribution. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 102–120.  相似文献   

15.
An extensive body of research has recently demonstrated patterns of parallel and/or convergent evolution that arise from divergent natural selection pressures exerted across environmental gradients. These studies, although providing some of our best empirical evidence for natural selection, have focused on rather narrow phylogenetic scopes, more often than not comparing patterns of morphological change among closely‐related taxa within a single genus. Organisms in replicated populations in these studies are often assumed to have accomplished convergence via similar underlying processes. However, such assumptions cannot be made when looking at evolution across broader phylogenetic and ecological spectra. In the present study, we assessed morphological change across a much broader scale to test whether similar evolutionary and developmental patterns underlie convergence. Specifically, we studied morphological change that has occurred in a novel lake environment (Lake Waccamaw, North Carolina, USA) where three phylogenetically‐disparate fishes representing different orders have speciated and independently evolved streamlined morphologies relative to their deeper‐bodied progenitors occupying nearby streams and coastal regions. Geometric morphometric analyses revealed that, although the bulk of shape change between environments is similar across taxa, significant species‐specific responses, concordant with differing expectations based on the ecologies of these taxa, were also found. Moreover, allometry analyses indicated that the developmental patterns underlying this change also differ across taxa. The present study provides evidence that, within a common environment, convergence can be achieved by different evolutionary and developmental patterns in phylogenetically‐ and ecologically‐disparate taxa. Finally, these results contradict the commonly‐held hypothesis that fishes should be more streamlined in streams than lakes and emphasize the need to also consider other environmental characteristics, such as water clarity and physical complexity, in studies of divergence. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 636–645.  相似文献   

16.
The small size and apparent external morphological similarity of the minute salamanders of the genus Thorius have long hindered evolutionary studies of the group. We estimate gene and species trees within the genus using mitochondrial and nuclear DNA from nearly all named and many candidate species and find three main clades. We use this phylogenetic hypothesis to examine patterns of morphological evolution and species coexistence across central and southern Mexico and to test alternative hypotheses of lineage divergence with and without ecomorphological divergence. Sympatric species differ in body size more than expected after accounting for phylogenetic relationship, and morphological traits show no significant phylogenetic signal. Sympatric species tend to differ in a combination of body size, presence or absence of maxillary teeth, and relative limb or tail length, even when they are close relatives. Sister species of Thorius tend to occupy climatically similar environments, which suggests that divergence across climatic gradients does not drive species formation in the genus. Rather than being an example of cryptic species formation, Thorius more closely resembles an adaptive radiation, with ecomorphological divergence that is bounded by organism‐level constraints. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 622–643.  相似文献   

17.
The genus Dioon occupies an important phylogenetic position as sister to the other Zamiaceae. However, its epidermal morphology is still poorly known. We employed scanning and transmission electron microscopy, confocal microscopy and light microscopy to examine the epidermal and cuticular morphology of 12 of the 14 currently recognized species of Dioon, examining cultivated plants and herbarium specimens. Epidermal characters separate Dioon quite clearly from the other genera of the cycads. Within the genus, the major subgroups can be distinguished by their epidermal morphology. Some characters, such as the degree of stomatal protection, reflect ecological specializations in species within the subgroups. Several epidermal characters of the crown group Dioon seem to be absent in the Cenozoic fossils usually associated with the genus, which have been used as calibrations in many recent molecular dating analyses. The presence of similar characters in a Mesozoic fossil adapted to volcanic stress offers a new key in the interpretation of Dioon evolution. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 236–254.  相似文献   

18.
In this study we investigated the phylogenetics of the Eurasian treecreeper (Certhia familiaris), a forest passerine with a wide Palaearctic range including Corsica, using three mitochondrial genes and three nuclear introns, and its phylogeographic history using the COI gene. Our phylogenetic results, including eight of the ten sub‐species currently recognized, support the monophyly of C. familiaris with respect to its Indo‐Asian sister species C. hodgsoni. C. familiaris comprises two lineages that diverged during the mid‐Pleistocene (c. 1 Myr): one palaeoendemic lineage has an allopatric range nowadays restricted to the Corsica island and the Caucasus region whereas the second one, more recent and widespread, is distributed over most of Eurasia and in northern China. The most likely scenario that may explain such a pattern is a double colonization of the western Palaearctic from the eastern range of the species. During the middle Pleistocene period, a first lineage expanded its range up into Europe but did not persist through glacial cycles except in Corsica and the Caucasus region. Later, during the upper Pleistocene, a second lineage began to diversify around 0.09 Myr, spreading towards the western Palaearctic from a unique refuge likely located in the eastern Palaearctic [correction added on 6 March 2015 after first online publication: 0.9 Myr amended to 0.09 Myr]. Apart from C. f. corsa, our results do not suggest any distinct evolutionary history for other sub‐species previously described on morphological grounds in Europe. Our study highlights the important conservation value of the Corsican treecreeper and emphasizes the major role of mature pine forests in the evolution of endemic bird taxa in Corsica. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115 , 134–153.  相似文献   

19.
Geckos are the only major lizard group consisting mostly of nocturnal species. Nocturnality is presumed to have evolved early in gecko evolution and geckos possess numerous adaptations to functioning in low light and at low temperatures. However, not all gecko species are nocturnal and most diurnal geckos have their own distinct adaptations to living in warmer, sunlit environments. We reconstructed the evolution of gecko activity patterns using a newly generated time‐calibrated phylogeny. Our results provide the first phylogenetic analysis of temporal activity patterns in geckos and confirm an ancient origin of nocturnality at the root of the gecko tree. We identify multiple transitions to diurnality at a variety of evolutionary time scales and transitions back to nocturnality occur in several predominantly diurnal clades. The scenario presented here will be useful in reinterpreting existing hypotheses of how geckos have adapted to varying thermal and light environments. These results can also inform future research of gecko ecology, physiology, morphology and vision as it relates to changes in temporal activity patterns. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, ●●, ●●–●●.  相似文献   

20.
Male (staminate) flowers of Dypsis possess either six or three stamens and/or staminodes, in contrast to most other palms, in which the basic stamen number is six (although polyandry is also common in palms). Significant variation among the tristaminate forms, both in stamen morphology and stamen position with respect to the perianth parts, indicates that stamen reduction from six to three has occurred more than once, and possibly several times within Dypsis. A few species include teratological forms with zygomorphic flowers; for example, Dypsis lantzeana normally possesses three antesepalous stamens, but in some specimens only the median outer (abaxial) stamen is expressed, perhaps indicating incipient zygomorphy correlated with complex synorganization. Inclusion of earlier historic genera such as Neophloga and Chrysalidocarpus within a broadly circumscribed Dypsis appears to be justified, although the informal taxonomic groupings within Dypsis require review, in particular the taxonomic significance of the different types of anther morphology. The discovery here that adnation of staminodes to the pistillode (complex synorganization) occurs in species other than D. mirabilis opens further questions about the taxonomic utility of this character in Dypsis, in which stamen/staminode development and adnation are apparently unusually labile. Such androecial–gynoecial adnation is otherwise rare in palms, as also in other monocots, in which probably the best‐known example occurs in orchids. Septal nectaries are present in some, but not all, staminate flowers in species of Dypsis. Dypsis bejofo is exceptional in that in staminate flowers the pistillode is distally bulbous and bears three prominent modified supralocular septal nectaries. Female (pistillate) flowers in Dypsis are syncarpous, normally pseudomonomerous (as in many other Arecoideae), and possess septal nectaries that effectively delimit the carpel margins and indicate insect pollination. There is a central solid transmitting tissue that extends from the placenta to three stylar canals. The stylar canals of the two sterile carpels are apparently functional, in addition to that of the fertile carpel. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 143 , 115?133.  相似文献   

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