A taxonomic reassessment of Blepharocarya F. Muell.

The specialized female and male inflorescences of Blepharocarya are analysed revealing that each is derived from a thyreoid inflorescence. This appears to be a characteristic of the Anacardiaceae. The occurrence of vertical intercellular secretory canals in the primary and secondary phloem is illustrated, whilst the presence of Rhus–type pollen is confirmed. These characters provide further support for the retention of the genus in the Anacardiaceae.     

Manipulation of bee behavior by inflorescence architecture and its consequences for plant mating

Angiosperms display flowers in many three-dimensional arrangements, but the functional significance of this diversity is largely unknown. We examined influences of inflorescence architecture on pollination and mating by quantifying the responses of bumblebees to three architectures and then using these observations as the basis of a model that simulated pollen dispersal. On artificial panicles, racemes, and umbels, each with 12 identical flowers, bees visited one more flower, on average, on umbels than on panicles (with racemes being intermediate). In contrast to this weak response, the consistency of foraging paths among flowers differed strongly among architectures (raceme > panicle > umbel). The simulation model revealed limited differences in self-pollination and pollen export among the three inflorescence designs when all flowers presented and received pollen, because mating differences depended on only the number of flowers visited. In contrast, in simulations of inflorescences on which pollen receipt and presentation were segregated so as to minimize interference among flowers, the consistency of movement paths governed mating. In this case, racemes self-pollinated much less than umbels (with panicles being intermediate), and racemes exported much more pollen than umbels and panicles. These effects have diverse consequences for the evolution of inflorescence architecture, flower design, and sexual segregation.     

Comparative floral morphology and anatomy of Anacardiaceae and Burseraceae (Sapindales), with a special focus on gynoecium structure and evolution

Anacardiaceae and Burseraceae are traditionally distinguished by the number of ovules (1 vs. 2) per locule and the direction of ovule curvature (syntropous vs. antitropous). Recent molecular phylogenetic studies have shown that these families are sister groups in Sapindales after having been separated in different orders for a long time. We present a comparative morphological study of the flower structure in both families. The major clades, usually supported in molecular phylogenetic analyses, are well supported by floral structure. In Anacardiaceae, there is a tendency to gynoecium reduction to a single fertile carpel (particularly in Anacardioideae). The single ovule has a long and unusually differentiated funicle, which connects with the stylar pollen tube transmitting tract in all representatives studied. In Anacardiaceae–Spondiadoideae, there is a tendency to form an extensive synascidiate zone, with a massive remnant of the floral apex in the centre; these features are also present in Beiselia (Burseraceae) and Kirkiaceae (sister to Anacardiaceae plus Burseraceae) and may represent a synapomorphy or apomorphic tendency for the three families. In core Burseraceae, gynoecium structure is much less diverse than in Anacardiaceae and has probably retained more plesiomorphies. Differences in proportions of parts of the ovules in Anacardiaceae and Burseraceae are linked with the different direction of ovule curvature. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 499–571.     

Cyanoneuron (Rubiaceae), a new genus from Borneo and Sulawesi

The genus Cyanoneuron is established to accommodate three Bornean and Sulawesi species previously placed in Myrioneuron . Two new species: C. grandiflorum and C. pedunculatum are described. All five species are illustrated. A survey of the character states including vegetative, inflorescence, floral, fruit, pollen, seed morphology and anatomy is given. The chromosome number has been counted for C. cyaneum, C. grandiflorum and C. pubescens. Cyanoneuron is tentatively included in the tribe Hedyotideae, but its affinity to genera inside this tribe is unknown.     

Morphology, anatomy, and taxonomic position of Pagameopsis (Rubiaceae-Rubioideae)

Morphological and anatomical features (including wood anatomy and pollen morphology) of the small neotropical genusPagameopsis (Rubiaceae-Rubioideae) are discussed and illustrated. The fused ovaries, fenestrate corolla tube, basally attached anther filaments, and absence of raphides are especially noteworthy.Pagameopsis is definitely not a member of the Psychotrieae because of significant differences in wood anatomy and gynoecial and fruit structure. A close affinity with Gaertnereae seems doubtful for similar reasons. The taxonomic affinities ofPagameopsis remain obscure. The genus shows similarities with several taxa of the Rubioideae, such as Coccocypseleae, Morindeae, Hedyotideae, andMetabolos. The absence of raphides, on the other hand, makes a position in the Rubioideae doubtful.     

Floral structure and development of Acoraceae and its systematic relationships with basal angiosperms

Flower development and anatomy of Acorus calamus and flower anatomy of A. gramineus were studied. Findings were compared with published reports on paleoherbs. Important developmental features include an abaxially median tepal that is initiated first and is similar to a flower-subtending bract and unidirectional flower development with an inversion of organ initiation sequence in the second tepal whorl. The mature gynoecium is largely synascidiate, but early development of carpels is plicate, and the apocarpous portion persists up to anthesis. The carpels form dorsal bulges on the style, enclosing longitudinal intercarpellary slits. The dominance of the synascidiate portion and the apical position of the placenta result from a late and distinct basal elongation of the gynoecium. Stigma, pollen transmitting tract, and ovary are filled with secretion. Secretory papillae are present from the stigma to the placenta; papillae also occur on the rims of the integuments of the ovules. In the uppermost part of the inflorescence, the adaxial floral sectors are reduced in number and structure, and at the apex of the inflorescence, a peloria-like structure is formed. Developmental and morphological similarities seem to be closer between Acorus and Piperales than between Acorus and other magnoliids.     

大血藤科植物的分类学研究

作者对大血藤科植物的花性、叶片内部结构形态、花粉形态、染色体核型及过氧化物酶和脂酶同工酶进行了比较研究,结果表明：１）大血藤科植物外形上的两性花,其雄蕊的形态退化、花药始终不开裂,为功能上的雌花,因此其花为单性,同株,同序或异序;１２）首次指出大血藤属植物的染色体数为２ｎ＝２ｘ＝２２,属小型染色体,与木通科植物２ｎ＝２ｘ＝３２、３０、２８的染色体数明显不同,支持Ｓｔａｐｆ（１９２６）将其从木通科分出另立为科的观点;３）单叶和复叶可出现于同一植株上,而且在叶片内部结构、花粉形态、染色体核型、过氧化物酶及脂酶同工酶等性状上,大血藤与单叶血滕间均无实质性的差异,因此将单叶血藤归并于大血藤中。     

Additional observations on Rhynchosperma quinnii (Medullosaceae): a permineralized ovule from the Chesterian (Upper Mississippian) Fayetteville Formation of Arkansas

New ovules from the Fayetteville Formation (Upper Mississippian) of Arkansas expand our knowledge of the morphology and anatomy of Rhynchosperma and suggest it was produced by a medullosan seed fern. Rhynchosperma has been described as radially symmetrical with a two-layered integument and vascularization in the integument only. The apical portion of the integument is ribbed; the nucellus is fused to the integument and apically differentiated into a dome-shaped pollen chamber. The vascular system is incompletely known and apparently restricted to the base of the integument. The new specimens are like Rhynchosperma in external shape, size, number of ribs, and numerous histological features. However, new data reveal that the nucellus is vascularized by a sheath of tracheids, the integument is vascularized by discrete bundles, the pollen chamber has a nucellar beak, and the nucellus is attached to the integument for a variable distance from the base. In addition, the integument is tripartite with an elaborate apical region; ribs formed by the integument are more pronounced at the apex; and internally open, hollow lobes form a stellate micropylar canal. The presence of a tripartite integument, the nature of the vascular system, the nucellus-integument attachment, the pollen chamber structure, symmetry, and the association with medullosan vegetative remains suggest medullosan affinity for these ovules and strengthens the evidence for the origin of the family before the end of the Lower Carboniferous.     

Pollen production in anemophilous species of the Poaceae family in Tetouan (NW Morocco)

Total pollen production per inflorescence and per square meter were studied in anemophilous species of the Poaceae family, to determine the relative contribution of each species to the total load of pollen released and to identify the species with the highest potential pollen emission. This was done by calculating the number of pollen grains per flower and per inflorescence and by estimating the density of inflorescences in an area of one square meter. Pollen production per inflorescence varied between 12,000 and 15 million grains, often being higher in the perennial species. Mountainous, grassland, riverside, and littoral areas contributed similarly to the amount of pollen grain production per square meter. Species such as Gaudinia fragilis, Hordeum murinum, Lolium rigidum, and Trisetaria panicea, with high pollen records, were found in all the studied areas. Aerobiological analysis will be undertaken to determine the main pollen season of Poaceae species. The results obtained are of great importance for respiratory health management in this region.     

On a new subsection of Pandanus section Cauliflora (Pandanaceae) with paniculate staminate inflorescence structure,distinctive leaf anatomy and pollen morphology

A new subsection, Pandanus section Cauliflora subsection Paniculiflora, is described to contain P. halleorum, on the grounds of the paniculate structure of its staminate inflorescence, a feature not known elsewhere within the genus Pandanus. Both leaf anatomy and pollen morphology appear to support this taxonomic separation.     

Anther diversity and function inVerticordia DC. (Myrtaceae)

Anther form and structure across the taxonomic groups inVerticordia were examined. The three anther types which were recognised — rectangular, oblong and saccate, accord well with the three subgenera into which the genus has been divided. The sporogenous part of the anther has a fairly typical angiosperm anatomy. However in many species there is a small or large gland in the upper filament/connective which contains lipidic contents. The anatomy of this structure is based on that of the oil glands which are ubiquitous in Myrtaceae primary tissues. However the gland is usually much larger than these and is schizolysigenous in origin. Evolutionary development of the anthers in the genus is related to pollination systems and the development of secondary pollen presentation from the upper style in some groups. Anther glands may have originally had a protective function for the sporogenous tissue. However in different groups the function has changed or the gland has disappeared. In some species in subgenusChrysoma (which does not have secondary pollen presentation) the gland contents seem to be an additional food source for pollinators. In other groups, with the development of secondary pollen presentation the protective function has become redundant and anther glands have either disappeared or produce contents which have become part of the process of pollen dispersal.     

REPRODUCTIVE BIOLOGY OF APIACEAE. II. CRYPTIC SPECIALIZATION AND FLORAL EVOLUTION IN THASPIUM AND ZIZIA

The classification of specialized floral syndromes has imposed a bias in the interpretation of pollination systems which may be either more generalized, or more specialized, than we have universally acknowledged. An analysis of floral biology in two umbellifer genera, Thaspium and Zizia, was undertaken in order to determine the extent to which cryptic floral or inflorescence variations determine pollination specialization despite a broad visitor spectrum and open reward system. Separate analyses were made of the primary attractants, nectar and pollen, and the secondary attractants, floral color and floral and inflorescence structure in conjunction with analyses of pollinator movements, stigmatic pollen loads and fruit set. All data support the conclusion that cryptic variation in floral and inflorescence characters enhance specialization for pollination by solitary bees or syrphid flies. In addition, evidence is presented for the importance of the oligolectic relationship between taxa of Thaspium and Zizia and the solitary bee, Andrena ziziae. The need for more experimental work both to further define the oligolectic relationship and to understand how floral and inflorescence color and structure affect insect movements is especially revealed by this study. The degree of pollination specialization in Thaspium and Zizia is not uncommon in Apiaceae and has important implications for floral evolution in this family and other plant groups with pollination systems categorized as “promiscuous.”     

A ballistic pollen dispersal system influences pollination success and fruit‐set pattern in pollinator‐excluded environments for the endangered species Synaphea stenoloba (Proteaceae)

The critically endangered Synaphea stenoloba (Proteaceae) has numerous scentless flowers clustered in dense inflorescences and deploys a ballistic pollen ejection mechanism to release pollen. We examined the hypothesis that active pollen ejection and flowering patterns within an inflorescence influence the reproductive success (i.e. fruit formation) of individual flowers within or among inflorescences of S. stenoloba in a pollinator‐excluded environment. Our results showed that: (1) no pollen grains were observed deposited on the stigma of their own flower after the pollen ejection system was manually activated, indicating self‐pollination within an individual flower is improbable in S. stenoloba; (2) fruit set in the indoor open pollination treatment and the inflorescence‐closed pollination treatment indicated that S. stenoloba is self‐compatible and pollen ejection can potentially result in inter‐floral pollination success; (3) fruit set in the inflorescence‐closed pollination treatment was significantly lower than that of indoor open pollination, indicating within‐ and between‐flower pollination events in an inflorescence are most likely limited, with pollination between inflorescences providing the highest reproductive opportunity; and (4) analysis of the spatial distribution of cumulative fruit set on inflorescences showed that pollen could reach any flower within an inflorescence and there was no functional limitation on seed set among flowers located at various positions within the inflorescence. These data suggest that the pollen ejection mechanism in S. stenoloba can enhance inter‐plant pollination in pollinator‐excluded environments and may suggest adaptation to pollinator scarcity attributable to habitat disturbance or competition for pollinators in a diverse flora. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170 , 59–68.     

Major plants foraged by bees for honey production in Ghana: mapping of bee floral sources for the development of the apicultural industry

Abstract

Honey is increasingly being used as a food supplement and to treat various diseases and disorders in Ghana. Information on floral nectar preferences of foraging honeybees is, therefore, imperative to increase production to keep pace with demand. However, in Ghana, these floral nectar preferences are yet to be investigated and identified. This study was conducted to determine bee forage sources in the three main agro-ecological honey-producing zones of Ghana. Forty-eight unblended honey samples sourced from beekeepers were analysed. Pollen spectra of the honey samples revealed 27 different pollen types of which eight were identified to family level, while 15 and four were at the level of genus and species, respectively. The results also showed that, in general, 48% of the analysed samples were unifloral honeys with the most important pollen types coming from Sapotaceae/Meliaceae, Anacardiaceae and Burkea africana. Combretaceae, Sapotaceae/Meliaceae and Anacardiaceae, as well as Lannea-type and Burkea africana were found to be the most frequent (with occurrence greater than 50%) sources of nectar utilised by bees to produce honey. The predominant pollen sources of the honeys in the three main apicultural zones of the country were Sapotaceae/Meliaceae and Anacardiaceae (Forest zone), Sapotaceae/Meliaceae and Lannea-type (Savannah–Forest transition zone) and Sapotaceae/Meliaceae, Anacardiaceae and Gynandropsis gynandra (Savannah zones). Identification of the major bee floral sources can be used as a guide by beekeepers in the location of their apiaries as well as reforesting disturbed sites with these plants to act as sources of bee forage.     

Pollen production in the Poaceae family

Total pollen production per inflorescence was studied in the most important species of the Poaceae family in the city of Córdoba in order to further our knowledge of the partial contribution of each species of this family to the total amount of pollen released into the atmosphere.

The contribution of grasses in a given area was estimated by counting the number of inflorescences in an area of one square meter. Four different representative areas of the city were selected. The number of pollen grains per anther and flowers per inflorescence was also estimated in order to obtain total pollen production per inflorescence.

Pollen production per inflorescence ranged from 14,500 to more than 22,000,000 pollen grains, the amount being clearly higher in the perennial species. Pollen production per square meter was higher in the mountains near the city and lower in areas of abandoned crops.

Only a few species are responsible for the majority of pollen produced. A phenological study is necessary in order to determine the temporal distribution of this pollen production and subsequent shedding.     

AEROBIOLOGY AND POLLEN CAPTURE OF ORCHARD-GROWN PISTACIA VERA (ANACARDIACEAE)

The phenology of pollen release and pollen capture by Pistacia vera was studied in the field and laboratory respectively. Inflorescences of Pistacia vera were examined in a wind tunnel to determine whether the behavior of airborne conspecific pollen around receptive flowers differed as a result of changes in the shape and size of the inflorescence. In addition, the behavior of unclumped (single) and clumped pollen grains was studied to determine differences in the probability of their capture. Wind speeds within a commercial orchard during pollen shedding averaged 0.9–2.2 m/sec and atmospheric pollen concentrations were highest between 0900–1100 hr MST. Each of three stages in inflorescence development (defined on the basis of the number of exserted stigmas) was examined under identical ambient airflow conditions with equal concentrations of airborne pollen (1,000 grains/m³). The general pattern of pollen grain motion involves direct inertial collision by windward surfaces and by sedimentation of pollen onto leeward surfaces; clumped pollen rarely sedimented onto leeward surfaces. Small changes in ambient wind speed (0.5 m/sec to 1.0 m/sec) produced significant changes in the pattern of pollen motion around inflorescences and altered the number of pollen grains captured by leeward surfaces. Thus, wind pollination in P. vera is affected both by windspeed and by the shape or size of flower clusters. Differences in the behavior of clumped and unclumped pollen result from their inertial properties and responsiveness to local changes in the direction and speed of airflow. Unclumped pollen has a higher probability of being captured by leeward surfaces. The apparent insensitivity of pollen motion to differences in inflorescence size may ensure equitable pollination during the acropetal development of flowers.     

Floral and seedling morphology and anatomy of Thalassodendron pachyrhizum den Hartog (cymodoceaceae)

Thalassodendron pachyrhizum den Hartog is dioecious with inflorescences on short laterals from upright stems. The male inflorescence consists of two flowers which are morphologically identical but developmentally different. Each male flower has two laterally fused anthers, each of which contains four loculi surrounding a vascular bundle. Filiform pollen grains are arranged in coils. The walls of pollen grains contain cellulosic microfibrils embedded in a protein and carbohydrate matrix, and lack an exine layer. The female inflorescence produces two morphologically and developmentally identical flowers, each having an ovary with a short style containing two vascular bundles and leading to two long, slender stigmas. Both male and female inflorescences are enclosed in several alternating bracts. The innermost bract differs from the others by lacking a ligule. Squamulae intravaginales are present in all inflorescences. In each inflorescence, only one ovary develops into the seed which germinates on the parent plant. Young seedlings have an aril-like structure which disappears at a later stage of seedling development. The seedling produces, firstly, an aberrant seedling leaf and a scarious seedling sheath, then several true foliage leaves and finally several root primordia. The mature seedling separates from its protecting bract and detaches from the parent plant. The floral and seedling morphology and anatomy are compared with other closely related genera in the Cymodoceaceae and unique features are assessed. The frequency of floral and seedling production is discussed in relation to the distribution of T. pachyrhizum.     

Inflorescence morphology of some South American Anacardiaceae and the possible phylogenetic trends

Barfod, A. 1988. Inflorescence morphology of some South American Anacardiaceae and the possible phylogenetic trends. - Nord. J. Bot. 8: 3–11. Copenhagen. ISSN 0107–055X.
The inflorescences of 15 native and one introduced species of South American Anacardiaceae belonging to the genera Anacardium, Loxopterygium, Mangifera, Mauria, Mosquitoxylon, Schinus, Spondias, Tapirira and Toxicodendron are described according to the terminology of Troll and coworkers. The tribal divisions in the Anacardiaceae are supported by the inflorescence morphology. Tribe Spondia-deae has paniculate inflorescences whereas tribe Anacardieae and tribe Rhoeae both have thyrsoids. Toxicodendron is exceptional for the tribe Rhoeae having axillary panicles. Thyrosids are hypothesized derived from panicles by a two step process including neoteny and enriching by cymose branching.     

NEW WORLD JUGLANDACEAE: A NEW SPECIES OF ALFAROA FROM MEXICO

Alfaroa mexicana is described as new. Certain aspects of the wood anatomy, inflorescence, pollen, staminate flower, and pistillate flower morphology are compared with previous findings on the three other species of Alfaroa and representatives of the closely related genus Engelhardia.     

The structure and potential loasaceous affinities of Schismocarpus

The affinity of Schismocarpus with Loasaceae has been questioned. Characteristic trichomic features are most often used for definition of Loasaceae, and Schismocarpus possesses a distinctly loasaceous syndrome of trichomes. Its inflorescence morphology is similar to that of Eucnide and Mentzelia , and it shares floral features with Eucnide. Although Schismocarpus possesses unique features (e.g., perennating "rootstock" and striate pollen) relative to Loasaceae, it is not aberrant considering the broad range of diversity that has been long accepted within the family. The apparently divergent floral morphology may be explained by its evolution of a "pollen flower" syndrome.