Morphology,nectar characteristics and avian pollinators in five Andean Puya species (Bromeliaceae)

Five Andean Puya species (Puya alpestris, Puya chilensis, Puya coerulea, Puya raimondii and Puya venusta) were studied to determine the relationship between their avian visitors, and plant morphology and nectar characteristics. Our results showed a significant relationship between nectar concentration, presence of sterile apex and avian pollinators's species. In contrast, nectar composition was not related to the frequency of avian visits. We found that Puya species were mainly visited by specialist nectarivorous birds such as hummingbirds (i.e., P. coerulea and P. venusta), lacked a sterile apex and produced high nectar concentration in low volumes. In contrast, species mainly visited by generalist passerines (i.e., P. chilensis and P. alpestris) were characterized by the presence of a sterile apex and production of highly diluted nectar in large volumes. In a mono-specific group we found that P. raimondii produces highly concentrated nectar in large volumes, and its flowers were visited by hummingbirds and passerine birds. We found no effect of nectar composition on bird's visits. Our study highlights the interplay between morphological traits, nectar characteristics and the ecological framework to explain specialized and generalized birds pollination systems.     

Uncovering tropical diversity: six sympatric cryptic species of Blepharoneura (Diptera: Tephritidae) in flowers of Gurania spinulosa (Cucurbitaceae) in eastern Ecuador

Diversification of phytophagous insects is often associated with changes in the use of host taxa and host parts. We focus on a group of newly discovered Neotropical tephritids in the genus Blepharoneura , and report the discovery of an extraordinary number of sympatric, morphologically cryptic species, all feeding as larvae on calyces of flowers of a single functionally dioecious and highly sexually dimorphic host species ( Gurania spinulosa ) in eastern Ecuador. Molecular analyses of the mitochondrial cytochrome oxidase-I gene from flies reared from flowers of G. spinulosa reveal six distinct haplotype groups that differ by 7.2–10.1% bp (uncorrected pairwise distances; N  = 624 bp). Haplotype groups correspond to six distinct and well-supported clades. Members of five clades specialize on the calyces of flowers of a particular sex: three clades comprise male flower specialists; two clades comprise female flower specialists; the sixth clade comprises generalists reared from male and female flowers. The six clades occupy significantly different morphological spaces defined by wing pigmentation patterns; however, diagnostic morphological characters were not discovered. Behavioural observations suggest specific courtship behaviours may play a role in maintaining reproductive isolation among sympatric species. Journal compilation  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 779–797. No claim to original US government works.     

Phylogenetics of Puya (Bromeliaceae): Placement, major lineages, and evolution of Chilean species

Puya (Bromeliaceae), a large genus of terrestrial bromeliads found throughout a range of elevations in the Andes and central Chile, is of great systematic, evolutionary, and biogeographical interest. This first molecular phylogenetic study of Puya and related bromeliads employs matK, trnS-trnG, rps16, and PHYC sequences. Chloroplast DNA, nuclear DNA, and combined DNA data all place Puya closest to subfamily Bromelioideae. Nuclear and combined data support Puya as monophyletic, and the two subgenera are nonmonophyletic. All data indicate that the Chilean species of Puya are early diverging within the genus, consistent with Chilean genera as the first-diverging members of subfamily Bromelioideae. Central Chile is identified as a key region for understanding the biogeographical history of Bromeliaceae, as is true with other South American plant groups. A complicated history involving early chloroplast capture and later secondary hybridization and/or introgression is seen in Chilean lineages. These events help explain the occurrence of sterile inflorescence tips, floral color and shape, and leaf indument. The ecological radiation of Puya appears coincident with the final, recent rise of the Andes and subsequent high-elevation habitat diversification. Additionally, geographical distribution, rather than moisture or elevational adaptations, correlates to species relationships. Evolution of CAM photosynthesis has occurred multiple times.     

Molecular phylogeny of the genus Philodendron (Araceae): delimitation and infrageneric classification

The genus Philodendron (Araceae) is a large neotropical group whose classification remains unclear. Previous classifications are based on morphological characters, mainly from the inflorescence, flower and leaf shape. The classification by Krause, with few modifications, is still the most commonly used system. To examine phylogenetic relationships in the genus, two ribosomal DNA nuclear markers, internal transcribed spacer (ITS) and external transcribed spacer (ETS), and the chloroplast intron rpl 16, were sequenced and analysed for more than 80 species of Philodendron and its close relative Homalomena . According to the resulting phylogeny, the genus Homalomena may be paraphyletic to the genus Philodendron . The inclusion of the American Homalomena species within the genus Philodendron might resolve this taxonomic problem. All three subgenera of Philodendron were revealed as monophyletic. Below the subgeneric level, the groups obtained in our phylogeny globally correspond to sections recognized in previous classifications. Among the morphological characters used by previous taxonomists to build their classifications, and which we optimized onto one of the most parsimonious trees, most characters were found to be homoplasious. However, leaf shape, characteristics of the sterile zone on the spadix and venation patterns are useful for delimiting subgenera and sections within the genus.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 13–27.     

A new species of Behuria Cham. (Melastomataceae: Merianieae) from Brazil

Behuria comosa Tavares, Baumgratz & Goldenberg is a new species from Minas Gerais and Espírito Santo, Brazil. It can be recognized by the branch nodes, sinuses of the leaf margins and domatia comose, leaves and inflorescence axes frequently three‐whorled, flowers five(–six)‐merous, calyx lobes broadly triangular and with the apex laterally flattened, and petals glabrous, thickly apiculate. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 489–492.     

Pollination of Kadsura longipedunculata (Schisandraceae), a monoecious basal angiosperm, by female, pollen-eating Megommata sp. (Cecidomyiidae: Diptera) in China

The plants of Kadsura longipedunculata (Schisandraceae) are monoecious and possess either red or yellow male flowers (the androecium), with yellow tepals, and yellow female flowers. All flower types simultaneously produce heat and floral odours (dominated by methyl butyrate) throughout a 4–5-h nocturnal period. The flowers are pollinated only by female, pollen-eating Megommata sp. (Cecidomyiidae). Pollen is the only reward, and female flowers use the same attractants as male flowers but offer no food (pollination by deceit). Open pollinated flowers in nature varied in fruit set from 8 to 92%. Megommata (subfamily Cecidomyiinae, supertribe Cecidomyiidi), consists of six described species, which feed on Coccoidea (scale insects) and are distributed worldwide.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 523–536.     

Patterns of inbreeding depression in a population of Brassica cretica (Brassicaceae): evidence from family-level analyses

In this investigation, we have collected family-structured data from a partly self-compatible, outcrossing population of Brassica cretica to estimate and compare the effects of one-generation selfing on different types of characters. Inbreeding not only depressed characters that should be positively correlated with fitness irrespective of habitat, e.g. germinability, leaf number and inflorescence size, but also resulted in later flowering, smaller and more asymmetric flowers, and an increased production of basal branches. Population-level estimates of inbreeding depression were similar in magnitude to estimates reported in other wild plant species. There was a tendency for direct components of fitness to exhibit a stronger response to inbreeding than other characters, but only when the differences between selfed and outbred offspring were measured in standard deviation units. Family-level estimates of inbreeding depression were weakly correlated across characters. Given these and other observations, we hypothesize that the genetic basis of inbreeding depression varies across the life cycle and that changes in local inbreeding will lead to shifts in the mean phenotypes of B. cretica populations. However, judging from data on current levels of population divergence, quite large changes in inbreeding will be required to influence large-scale patterns of variation in this species.  © 2002 The Linnean Society of London. Biological Journal of the Linnean Society , 2002, 76 , 317–325.     

Characterization of unisexual flower development in the endangered mahogany tree Swietenia macrophylla King. (Meliaceae)

The selection of candidate plus trees of desirable phenotypes from tropical forest trees and the rapid devastation of the natural environments in which these trees are found have created the need for a more detailed knowledge of the floral and reproductive biology of tropical tree species. In this article, the organogenic processes related to unisexual flower development in tropical mahogany, Swietenia macrophylla , are described. Mahogany inflorescences at different developmental stages were evaluated using scanning electron microscopy or optical microscopy of histological sections. The unisexual flowers of S. macrophylla are usually formed in a thyrse, in which the positions of the female and male flowers are not random. Differences between male and female flowers arise late during development. Both female and male flowers can only be structurally distinguished after stage 9, where ovule primordia development is arrested in male flowers and microspore development is aborted in female flower anthers. After this stage, male and female flowers can be distinguished by the naked eye as a result of differences in the dimensions of the gynoecium. The floral characteristics of S. macrophylla (distribution of male and female flowers within the inflorescence, and the relative number of male to female flowers) have practical implications for conservation strategies of this endangered species.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 529–535.     

Revision of the Malagasy species of the genus Tricalysia (Rubiaceae)

The Malagasy representatives of the large African genus Tricalysia (tribe Coffeeae s.l.) are revised. Three Malagasy species were hitherto recognized in the genus, namely T. cryptocalyx , T. madagascariensis , and T. ovalifolia . In this study, two species, T. boiviniana and T. leucocarpa , are transferred from the genus Hypobathrum and seven new species and two new subspecies are described, raising the species number for Tricalysia to a total of 12. This marked increase in species number is a recurring pattern for many Malagasy genera in systematically poorly known families such as Rubiaceae. All the species are described in detail and illustrated, and a list of exsiccatae and a distribution map are provided. Furthermore, the characters of the Malagasy taxa are compared with those of the continental African species, and their infrageneric status is discussed. With the exception of T. ovalifolia , a member of subgenus Empogona , all Malagasy species belong to subgenus Tricalysia . Because of their unisexual flowers, these species cannot be accommodated within one of the four existing sections in subgenus Tricalysia . A new section, Androgyne , is therefore recognized.  © 2007 National Botanic Garden of Belgium. Journal compilation © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 83–126.     

The genus Borassus (Arecaceae) in West Africa, with a description of a new species from Burkina Faso

Borassus akeassii Bayton, Ouédraogo & Guinko sp. nov. (Arecaceae) is described as a new species from western Burkina Faso in West Africa. It has been confused with the widely distributed African species B. aethiopum and more recently with the Asian B. flabellifer . However, it is distinguished by its glaucous, green leaves with weakly armed petioles and a characteristic pattern of lamina venation. The fruits have a pointed apex and are greenish when ripe, and the flowers of the pistillate inflorescence are arranged in three spirals. The pollen has a reticulate tectum and distinctive ornamentation. The distribution of B. akeassii is discussed and the status of the varieties of Borassus aethiopum (var. bagamojensis and var. senegalensis ) is examined.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 419–427.     

Morphological variation in Puya (Bromeliaceae): an allometric study

A group of representative species of the genus Puya was studied to determine if there are allometric relationships between vegetative and floral parts, whether these relationships correlate with their pollination system and if plant size is correlated with elevation and latitude. Fifty-three species representing the morphological variation and distribution of the genus were studied. Total plant height, as well as leaf, inflorescence, petal and sepal length were measured and these data subjected to univariate and multivariate analyses. To test for correlation between plant size and altitudinal and latitudinal distribution, ANOVAs were performed. When the pollination system of a species is known, additional multivariate and univariate analyses were also performed. The results indicate that the characters studied are correlated with a size component, exhibiting positive allometry for sepal and petal length and negative allometry for leaf length. Inflorescence length is an isometric character. There was no significant correlation between plant size and altitudinal or latitudinal distribution. The ANOVAs show that the only character correlated to pollinator type was petal length. Small plants with small flowers are correlated to pollinators such as insects, while medium to large plants with medium to large-sized flowers are correlated with pollinators such as birds and bats. Large plants have small flowers, that are more evident and attract more pollinators.     

Relationships between floral characters, pollination mechanisms, life forms, and habitats in Araceae

The floral traits of the inflorescences of angiosperms have coevolved to ensure and maximize pollination success. Other factors believed to influence floral architecture are external (for example, ecological) to the inflorescence. In order to understand the relationships between such factors and floral characters, 12 floral traits were measured in 54 species of Araceae. An analysis was performed to determine how these traits are linked to the following: (1) self-pollination capacity; (2) life form (evergreen versus seasonally dormant); (3) climatic conditions; and (4) type of pollinator (i.e. flies, bees, or beetles). A significant difference was found between the pollen to ovule ratio of the species able to self-pollinate and those unable to self-pollinate. Evergreen and tropical aroids produced a larger number of gametes than did seasonally dormant and temperate taxa. Finally, several floral traits, such as pollen volume and number, number of female flowers, and flower sexual type (unisexual or bisexual), showed clear differences between the three pollinator types. Variations in floral traits between the different life forms and climatic conditions are discussed with respect to pollination efficiency and properties of the growing season. The pollen to ovule ratio cannot be considered as an accurate indicator of breeding systems in aroids because of the particular pollination ecology of the family.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 29–42.     

Character divergences and convergences in canopy-dwelling Loranthaceae

The Loranthaceae is the largest plant family with aerial branch parasites termed mistletoes. Three genera of Loranthaceae are terrestrial root parasites and the remaining 72 genera are aerial parasites. Several characters, including habit, haustorial type, germination pattern, pollen morphology, chromosome number, inflorescence morphology and flower merosity, fusion, symmetry and size, are considered to reflect evolutionary relationships within the family. Convergence is a common evolutionary pattern and can confound interpretations of evolution. We investigated character evolution by mapping character states onto a phylogenetic tree based on the nuclear ITS and chloroplast trnL–trnF regions. Convergences in form were found in several characters, including habit, haustorial type, flower symmetry and merosity. These convergences typically correspond to ecological parameters such as pollination syndrome or stresses associated with the canopy habit. Other characters such as chromosome number and germination pattern illustrate divergent evolution among clades.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 101–113.     

Pollen morphology of the Swertiinae (Gentianaceae): phylogenetic implications

Recent molecular surveys of the Swertiinae (Gentianaceae–Gentianeae) revealed unexpected phylogenetic relationships, including polyphyly of the genera Gentianella , Jaeschkea , Lomatogonium and Swertia . To find new non-molecular characters supporting the phylogeny, we examined the exine variation of 73 species of all major lineages of subtribe Swertiinae using environmental scanning electron miscroscopy supplementing older, mainly light microscopical, studies. In contrast to previous studies, we were able to pick out taxa from phylogenetic key positions with particular focus on Swertia . Many distantly related taxa such as parts of Frasera , Gentianopsis , Halenia , Gentianella , Megacodon and several lineages of Swertia share a striate–reticulate or reticulate exine pattern. This is interpreted as the plesiomorphic character state of Swertiinae. There is also considerable variation of derived patterns; for example, different types of microechinate or almost smooth pollen was repeatedly observed in distantly related groups. Another extreme was the ring-shaped reticulation found in a North American species of Gentianopsis . Unfortunately, major relationships as revealed by molecular analyses were rarely supported because of the abundance of the plesiomorphic type and homoplasy even on low taxonomic levels; for example, within Lomatogonium . Exine variation was particularly useful in characterizing independent lineages of Swertia . For example, according to pollen characters and in agreement with other data, the Asian Swertia cuneata is a sister group of a strongly diversified African lineage and Swertia yunnanensis , which is rather aberrant in flower morphology, seems close to parts of Lomatogonium .  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 323–341.     

Polyploidy in Aconitum subgenus Lycoctonum (Ranunculaceae)

Chromosome numbers and morphology in 22 populations belonging to 11 taxa of Aconitum subgenus Lycoctonum (Ranunculaceae) from China were studied. Some taxa were diploid, with 2 n  = 16, but four species and two varieties were found to be tetraploid, with 2 n  = 32. They are concentrated in the Hengduan Mountains region in south-west China, indicating that polyploidy could have played an important role in the speciation of the subgenus in this region, one of the areas of the world with a high concentration of endemic species. The relationships of some of the species are discussed.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 343–353.