Botanical Journal of the Linnean Society

EDWARDS, DIANNE; RICHARDSON, JOHN B.; AXE, LINDSEY; DAVIES, KEVIN L.

doi: 10.1111/j.1095-8339.2011.01207.xpmid: N/A

AbstractAs part of a study to explore diversity and disparity in Early Devonian terrestrial vegetation, several hundreds of sporangia with in situ spores have been isolated from a Lochkovian locality in Shropshire. These include a small number (seven) of sporangia showing dehiscence into four valves and containing permanent sculptured dyads, belonging to the Cymbohilates horridus complex and C. cymosus, which are recorded in coeval dispersed spore assemblages. A further, previously described, mesofossil comprises an incomplete sporangium containing C. horridus that terminates a naked isotomously branching stem with stomata. The valvate sporangia are placed in a new genus, Partitatheca, containing four species, P. splendida (type), P. horrida, P. densa and P. cymosa, their names reflecting the names of the dispersed spore species and varieties. Complex ultrastructure in the walls of the dyads is similar to that in earlier dyads in the Dyadospora complex where it provides evidence for a hepatic affinity of the earliest embryophytes, but the new taxa present a combination of bryophyte and tracheophyte characters and are considered to represent a new embryophyte lineage. General discussion includes the development of dyads, more particularly their relevance to understanding the diversity in meiotic processes, and the disappearance of dyads from the dispersed spore record prior to the Middle Devonian.

CISTERNAS, MAURICIO A.; SALAZAR, GERARDO A.; VERDUGO, GABRIELA; NOVOA, PATRICIO; CALDERÓN, XIMENA; NEGRITTO, MARÍA A.

doi: 10.1111/j.1095-8339.2011.01200.xpmid: N/A

AbstractThe phylogenetic relationships of subtribe Chloraeinae, a group of terrestrial orchids endemic to southern South America, have not been satisfactorily investigated. A previous molecular phylogenetic analysis based on plastid DNA supported the monophyly of Chloraeinae and Gavilea, but showed that Chloraea is non-monophyletic and that the sole species of Bipinnula analysed is sister to Geoblasta. However, that analysis included only 18 of the 73 species belonging to this subtribe. Here, the phylogenetic relationships of Chloraeinae were assessed by analysing aproximately 7500 bp of nucleotide sequences from nuclear ribosomal internal transcribed spacer (ITS) and plastid DNA (rbcL, matK, trnL-trnF, rpoB-trnC) for 42 species representing all four currently accepted genera of Chloraeinae and appropriate outgroups. Nuclear and plastid data were analysed separately and in combination using two different methods, namely parsimony and Bayesian inference. Our analyses support the monophyly of Chloraeinae and their inclusion in an expanded concept of Cranichideae, but none of the genera of Chloraeinae that includes more than one species is monophyletic. Gavilea and Bipinnula are paraphyletic, with Chloraea chica nested in Gavilea and Geoblasta penicillata in Bipinnula. As currently delimited, Chloraea is polyphyletic. The taxonomic changes proposed recently are for the most part not justifiable on phylogenetic grounds, except for recognition of the monotypic genus Correorchis. The lack of resolution for the relationships among species of ‘core’ Chloraea suggests a relatively recent diversification of this group. The current generic classification is in need or revision, but additional study is advisable before carrying out further taxonomic changes.

SHUTTLEWORTH, ADAM; JOHNSON, STEVEN D.

doi: 10.1111/j.1095-8339.2012.01216.xpmid: N/A

AbstractPollinator-mediated convergence in floral traits is the fundamental basis for pollination syndromes, but it has seldom been rigorously analysed. Here we synthesize information on a guild of South African plants that are pollinated by functionally similar pompilid wasps in the genus Hemipepsis and investigate the extent of trait convergence in guild members. The guild includes members from three plant families (Apocynaceae, Orchidaceae and Asparagaceae subfamily Scilloideae) and contains remarkably high levels of functional specialization with 18 of the 23 known guild members being pollinated exclusively by Hemipepsis wasps. The distribution of the guild is centred in the moist upland grasslands of eastern South Africa. Qualitative similarities among guild members include dull greenish- or brownish-white flowers, often with purple blotches, mid-summer flowering, sweet spicy scent and exposed nectar. To assess the extent of convergent evolution within the guild, we compared floral traits of guild members with those of congeneric non-wasp-pollinated species. Guild members typically produce moderate volumes (> 4 µL per flower per day) of concentrated (> 50% sugar by weight) sucrose-dominant nectar. The nectar properties of guild members did not, however, differ significantly from those of congeneric species pollinated by other vectors. Non-metric multidimensional scaling of scent data for 15 guild members and 17 congeners (obtained through gas chromatography–mass spectrometry of headspace samples and supplemented with published data) yielded little evidence for convergent evolution in the overall scent composition of guild members. However, convergence in floral spectral reflectance was evident in the guild members; in particular, loci for colours of guild members were significantly closer to the guild centroid than loci for colours of congeners, and they formed a distinct cluster in the blue to blue–green region of the hymenopteran colour hexagon. The colours of guild members were also significantly closer to the colour of background vegetation than those of congeneric species, suggesting a role for cryptic colouring in this system. These results confirm convergence in the floral colours of plants that are pollinated by Hemipepsis spider-hunting wasps, but also suggest that other traits, such as nectar properties, do not necessarily evolve during shifts between pollination systems. Identification of particular scent compounds and non-sugar nectar constituents that influence wasp behaviour will be essential for illuminating the extent of biochemical convergence in the guild members.

LEY, ALEXANDRA C.; CLAßEN-BOCKHOFF, REGINE

doi: 10.1111/j.1095-8339.2011.01202.xpmid: N/A

AbstractThe flowers of Marantaceae (∼ 550 species) exhibit a highly derived pollination mechanism within Zingiberales, with a rapid and irreversible style movement based on a close synorganization of different floral parts. Given the complexity of the structure, we assume that little variation is possible if functionality is to be maintained. To test this, we investigated how much floral diversity exists in the clade and whether this diversity potentially influences the breeding system and placement of pollen on the pollinator. Flowers of 66 species covering the five major phylogenetic clades of the family were analysed. All species are similar in their basic flower construction: the fleshy staminode forms the tunnel-shaped roof of the flower and narrows the tube with stiff swellings, and the hooded staminode holds the style under tension and narrows the flower entrance with its trigger appendage. Despite morphological diversity of the pollination apparatus, functionality is maintained by coordinated variation of the fleshy and hooded staminodes. Autogamy is usually avoided by herkogamy. However, in a few exceptions, subtle morphological changes alter the breeding system from allogamy to autogamy. Variable floral proportions allow for differential pollen deposition potentially causing mechanical isolation between sister taxa. This study clearly illustrates that structural variation is not only present in the highly synorganized flowers of Marantaceae, but that it also creates potentially new options for evolutionary diversification.

PERUZZI, LORENZO; MANCUSO, ELISA; GARGANO, DOMENICO

doi: 10.1111/j.1095-8339.2011.01204.xpmid: N/A

AbstractThe bulbous geophyte Fritillaria montana is partially self-compatible and capable of switching gender. Small flowering plants produce only single male flowers, but larger plants produce hermaphrodite or, rarely, male and hermaphrodite flowers. Eight populations in peninsular Italy were sampled to determine the frequency and size distributions of male and hermaphrodite plants, and to determine the relationship of plant size to male and hermaphrodite flower production. Male plants were significantly smaller than hermaphrodites and made up 14.5–47.8% (100% in one small population) of flowering plants within populations. There were no significant differences in male fitness among female-sterile and hermaphrodite flowers, as they both possessed full and comparable fertilizing power. Therefore, the gender variation observed in F. montana is likely to depend on resource-dependent sex allocation. From an evolutionary perspective, we highlight the occurrence of similar mechanisms of gender variation in other representatives of the order Liliales.

ŁUCZAJ, ŁUKASZ JAKUB; KUJAWSKA, MONIKA

doi: 10.1111/j.1095-8339.2011.01205.xpmid: N/A

AbstractBotanists are an overlooked group of informants in ethnobotanical studies. The aim of this study was to assess their potential as sources of original ethnobotanical information. Wild food plants remembered by Polish botanists from their childhood were freelisted by 71 botanists. The results were compared with several ethnobotanical studies: three from the 21st century and one from the mid-20th century. The botanists listed 123 species (mean of 9.3 species per individual). Although the average number of personal freelists was slightly lower for botanists than for local key informants in two of the other studies (11 and 13, respectively), the total list of species was longer than in any other Polish ethnobotanical study. Two of the ethnobotanical studies supplied richer material on past famine plants, whereas the botanists mentioned many alien plants and plants from urban habitats not mentioned in the ethnographical study. It can be concluded that botanists are possibly the best source of information for studies of contemporary or new uses of plants, but are inadequate for uses that are dying out.

RONEL, MICHAL; LEV-YADUN, SIMCHA

doi: 10.1111/j.1095-8339.2011.01211.xpmid: N/A

AbstractTo examine whether spininess evolved at random or differently in various life forms and plant organs, we characterized spiny, thorny and prickly organs in the entire wild flora of Israel (294 such species). Of the species, 63.3% defended their reproductive organs (the most-defended organ) and 67.0% defended various non-reproductive organs. Ninety-three species defended both their reproductive organs and at least one other part; 48.3% defended their leaves and 36.4% their stems and branches. Spiny wings defended stems and branches only in herbaceous (annual or perennial) species. There were clear differences between the life forms. Annuals and perennial herbs defended mostly their reproductive organs (95.7 and 83.0%, respectively), dwarf shrubs defended mostly their leaves (54.2%) and shrubs and trees mostly their branches (89.7 and 76.2%, respectively). Trees do not defend their reproductive organs by associated sharp appendages. The differences in defence on various organs among different life forms may influence the results of meta-analysis studies of the optimal defence allocation if such differences are not taken into account. We noted spine, thorn and prickle colours for 167 species with yellow, red, orange and white being the dominant, supporting hypotheses about spines being visually aposematic.