Janusia anisandra (A. Juss.) Griseb (Malpighiaceae): The first case of enantiostyly in oil-flower species

Enantiostyly is a floral polymorphism characterized by style deflection to the right and left, which results in flowers with mirror images. To date, enantiostyly occurs only in species that offer pollen or nectar as floral resource. Here we describe the first case of enantiostyly in an oil-flower species. Janusia anisandra (A. Juss.) Griseb (Malpighiaceae) shows right and left-styled flowers in individuals occurring in an area of tropical dry forest in Northeastern Brazil. We described the floral morphology, investigate the reproductive system, and made focal observations of flower visitors behaviour. J. anisandra has morphological traits that are part of the floral conservatism found in the neotropical species of Malpighiaceae, which preserves features that are decisive for the interaction with oil-collecting bees of the Centridini tribe, performing a highly specialized pollination system. The six stamens (two major and four smaller), located in the center of the flower, characterizes heteranthery, an intrafloral polymorphism, in which the stamens differ in shape, size, and function and is commonly associated with enantiostyly. We identified the two floral morphs in the same individual, characterizing a monomorphic enantiostyly; each of the morphs differs by lateral displacement of the style to the right or to the left, always accompanied by one larger stamen. The species is moderately self-compatible. Four species of solitary bees of the genus Centris were registered visiting the two morphs of J. anisandra flowers. Centris aenea and C. fuscata were the main pollinators, performing 65% of the visits. This new discovery of a classical monomorphic enantiostyly in J. anisandra opens the way for investigations in the evolution of this system in oil-secreting flowers.     

Relationships between floral organization, architecture, and pollination mode inDillenia (Dilleniaceae)

The flowers ofDillenia are highly elaborate pollen-flowers adapted to buzzpollination byXylocopa bees. Two major forms of floral architecture (revolver flowers and roundabout flowers) are associated with two different pollination modes. In the first (e.g.,D. suffruticosa), the pollination organs are connivent to a cone; the pollinator grasps the entire cone with its legs and buzzes it; it revolves around its axis and repeats the buzzing in different positions. In the second (e.g.,D. alata, D. philippinensis), the stylar branches are spreading and the stamens are arranged in two sets of two different forms and colourations. The inner set has fewer and longer stamens that are cryptic pollination stamens; those of the outer set are shorter but optically conspicuous feeding stamens. The pollinator squeezes itself under the stylar branches and handles only the outer set by grasping part of the set at a time; it moves tangentially around the flower with several buzzing-stops; when buzzing pollen is sprayed onto its side and back from the inner stamen set. Centrifugal polyandrous androecia are a constitutive feature of flowers inDilleniaceae. InDillenia the centrifugal initiation of stamens proceeds for an unusually long time and is still not finished when the gynoecium is completely closed (in contrast toTetracera). The differentiation of heteranthery seems to be functionally correlated with the extended centrifugal inception. The latest formed stamens are small and sterile in many species. Generic features ofDillenia flowers can be understood from the roundabout architecture: big size, increased number of carpels, syncarpy forming a firm pedestal and spreading firm stylar branches with small, concave stigmas at the end, stamens with short, stout filaments and much elongated poricidal anthers, heteranthery, recurved stamens of the inner set.Dedicated to emer. Univ.-Prof. DrFriedrich Ehrendorfer on the occasion of his 70th birthday     

THE BREEDING SYSTEM OF OXALIS SUKSDORFII

The Pacific Coast species Oxalis suksdorfii (section Corniculatae) is morphologically tristylous. Flowers of the 3 kinds of plants present in natural populations differ in style length, stamen length, pollen size, stigma size and orientation, and stylar pubescence. Experimental studies and field observations indicate that plants with long-styled flowers are weakly self-compatible and show little differentiation in size or compatibility relationships of pollen from the 2 sets of stamens. Plants with mid-styled flowers have strongly differentiated pollen, but produce few capsules or seed after any artificial or natural pollinations. Plants with short-styled flowers are self-incompatible and show slight pollen differentiation. The data presented suggest that O. suksdorfii approaches functional dimorphism since the mid-styled form contributes little pollen and few seeds in sexual reproduction. The species may be in the process of losing the mid-styled form completely and provides a model of certain physiological and morphological changes which may have accompanied elimination of the mid-styled form in other Oxalis species. The abundance of plants with mid-styled flowers in natural populations suggests, however, that this form may be retained because it contributes to general population fitness, or because the genetic control of heterostyly in this species prevents its elimination.     

Comparative floral development in Lithospermum (Boraginaceae) and implications for the evolution and development of heterostyly

? Premise of the study: The evolution and development of floral developmental patterns were investigated in three heterostylous and three homostylous species of Lithospermum to determine whether species that independently acquired the same floral form follow the same pattern of development or different patterns. ? Methods: Using light and scanning electron microscopy, we observed developmental patterns in flowers at different stages of maturity. These patterns were compared within individual species, between heterostylous morphs, and among heterostylous and homostylous species. ? Key results: Although heterostyly has been determined by phylogenetic analysis to have originated independently in each of the heterostylous species, flowers of the long-style morph of each species follow similar patterns of gross development, as do those of the short-style morph. In addition, the flowers of each morph develop in a manner similar to those of their respective homostylous, herkogamous relatives. However, the developmental patterns of the stylar epidermal cells differ among these species and between heterostylous and homostylous species. ? Conclusions: Floral developmental patterns in homostylous species provide evidence that modification of specific traits, such as patterns of stylar growth, can lead to the evolution of heterostyly. The developmental changes that affect the positions of the stigmas and anthers in each morph likely involve either temporal or spatial modifications of gene function. The floral developmental patterns described here and the occurrence of multiple types of herkogamy within some species of Lithospermum provide evidence that heterostylous species in the genus have originated via distinct evolutionary developmental pathways.     

“金虎尾路线”植物的花进化与传粉转变

以金虎尾科植物地理分布格局及迁移历史总结出来的“金虎尾路线”, 是解释热带植物洲际间断分布与长距离扩散格局的重要模式。金虎尾路线阐明了金虎尾科植物历史时期7次独立的从起源中心(南美洲)向旧世界(非洲和亚洲)的洲际长距离扩散事件。本文总结了金虎尾路线植物起源地与扩散地主要类群的花部特征与传粉系统, 以探讨这些类群及类似植物长距离扩散后的花进化与传粉转变等适应规律。金虎尾科的南美洲类群都有分泌油脂的萼片腺体, 花的形态结构非常保守, 是与美洲当地特有的条蜂科集油蜂长期协同进化的结果。金虎尾科的非洲类群花保守性消失, 花白色、辐射对称且无萼片腺体, 繁育系统为雄花-两性花异株(功能性的雌雄异株), 传粉者是采集花粉的蜜蜂科昆虫。亚洲的一些属发生了类似非洲类群的泛化适应转变, 但风筝果属(Hiptage)出现了镜像花、异型雄蕊和极度反折的花瓣, 且传粉者是亚洲特有的大蜜蜂(Apis dorsata), 显示出了非常特化的适应性转变。风筝果属所在支系的现存类群涵盖了南美洲、中美洲、非洲和亚洲等地的地方特有属, 体现了金虎尾路线整个迁移历史过程, 是认识金虎尾路线及其进化适应规律的关键类群, 值得在今后的研究中加以重视。     

The evolution of polymorphic sexual systems in daffodils (Narcissus)

Narcissus, the daffodil genus, exhibits an unusual diversity of sexual systems, with populations that are monomorphic, dimorphic or trimorphic for style length. Associated with this variation are striking differences among species in floral morphology and pollination biology. This diversity provides an opportunity to investigate the evolution of mating polymorphisms, and to determine how floral morphology promotes transitions among sexual systems. Because of the absence of heteromorphic incompatibility in Narcissus, floral morphology plays a key role in governing patterns of outcrossed mating. Phylogenetic evidence indicates that stylar monomorphism is ancestral in the genus, with multiple origins of stylar polymorphism, including independent origins of stigma-height dimorphism, distyly and tristyly. Sexual polymorphisms have evolved only in lineages with narrow floral tubes that are pollinated by Lepidoptera and/or long-tongued bees. Populations of polymorphic Narcissus species are typically dominated by the long-styled morph and display imperfect reciprocity in the positions of sexual organs. These features are consequences of the unusual association between stylar polymorphism and a self-incompatibility system that permits intramorph mating.     

Errata

In south-eastern Arizona, heterostylous (often trimorphic) populations of Oxalis alpina (Rose) Knuth are visited most commonly by females of the solitary bee Heterosarus bakeri Cockerell. Bees collect pollen from flowers and are presumed to be the major pollinators of O. alpina in this region. Analysis of pollen loads from the corbiculae of H. bakeri suggests that individual bees may specialize temporally on different floral forms. However, the apparent preferential collection of pollen probably results from spatial segregation of morphs and the localized foraging behaviour of bees rather than preference on the part of individual bees for particular stylar forms. As a group, bees appear to visit floral morphs of O. alpina indiscriminately, even though individual bees may have a preponderance of pollen from one morph type. Despite spatial segregation leading to pollinator flights between members of the same incompatibility group, capsule and seed production in populations of O. alpina is high for all forms. Loss of the mid form in some populations cannot be attributed to pollinator preferences for individual style morphs.     

Reproductive biology of Nymphaea capensis Thunb. var. zanxibariensis (Casp.) Verdc. (Nymphaeaceae)

Anthesis in Nymphaea capensis var. zanzibariensis is diurnal with flowers opening and closing for three consecutive days. On the first day of anthesis, the stigmatic papillae secrete fluid and the outermost anthers are dehiscent. On the second day of anthesis the stamens form a cone above the dry stigmatic cup. The middle stamens open and turn outward. On the third day of flowering, all the stamens open and the dry stigmatic cup is exposed. The flowers are homogamous and not protogynous as the other Nymphaea. The gynoecium of the self-compatible N. capensis var. zanzibariensis , is characterized by a wet papillate stigma, a short hollow style, and secretory cells on the ventral surface of the ovary. The pollen is released on the receptive stigma. Following initial growth in intercellular spaces in the transmitting tract of the stigma, pollen tubes travel through the stylar canal and into the ovary.     

Pollination of Angelonia cornigera Hook. (Scrophulariaceae) by Long-Legged, Oil-Collecting Bees in NE Brazil

Abstract: The pollination of Angelonia cornigera Hook. (Scrophulariaceae) was studied in Caatinga vegetation, in the municipality of Buíque, Pernambuco state, northeastern Brazil. The plant is a perennial of open areas. Up to 60 flowers are produced in terminal, leafy racemes. The flowers are violet, strongly zygomorphic, of gullet type, with a pair of posterior pockets. Each pocket contains a patch of oil-producing glandular hairs (elaiophore). The flowers were only visited, and pollinated, by oil-collecting female bees of the Apidae-Apinae: Centris hyptidis and Tapinotaspis spec. nov. 1. These two bees differ considerably in size but they share the peculiarity of possessing one pair of disproportionately elongate legs suitable to gain access to the concealed elaiophores. In C. hyptidis, it is the front pair, whereas in T. spec. nov. 1 the mid pair of legs is elongated. T. spec. nov. 1 exhibited two modes of visiting behaviour. Angelonia cornigera is self-incompatible; it does not set fruits from spontaneous or manual self-pollination. This is the fifth observed species of the genus Angelonia whose flowers are adapted to oil-collecting bees in the Caatinga formation. Its flowers deviate in several aspects from the other studied Angelonia spp. regarding pollination relationships. New data on A. hirta and A. tomentosa are appended.     

Developmental morphology of the flower of <Emphasis Type="Italic">Dracontium polyphyllum</Emphasis> in the context of the phylogeny of the Araceae

The inflorescence of Dracontium polyphyllum consists of 150 – 300 flowers arranged in recognisable spirals. The flower has 5 – 6 (90% of observed specimens), or 7 broad tepals enclosing 9 – 12 stamens (occasionally 7) inserted in two whorls. The gynoecium is trilocular (90% of observed specimens) or tetralocular. The tetralocular gynoecia are found at random among the trilocular gynoecia. Each locule encloses an ovule inserted in an axile position, in the median portion of the ovary. Each carpel has its own stylar canal. However, in the upper portion of the style, there is only one common stylar canal. Floral organs are initiated in an acropetal direction in the following sequence: tepals, stamens, and carpels. During later stages of development, the tepals progressively cover the other floral organs. The first floral primordia are initiated on the upper portion of the inflorescence. During early stages of development, the floral primordia have a circular shape. The tepals are initiated nearly simultaneously. During later stages of development, the first whorl of stamens develops in alternation with the tepals and is followed by a second whorl of stamens. The trilocular or tetralocular nature of the ovary is clearly visible during early stages of development of the gynoecium. Recent molecular studies show that Anaphyllopsis A. Hay and Dracontium L. are closely related. However, although pentamerous flowers have been observed in Anaphyllopsis, the developmental morphology of the flower of Dracontium is different from that of Anaphyllopsis.     

Pterandra pyroidea: a case of pollination shift within neotropical Malpighiaceae

Background and Aims

Most Neotropical species of Malpighiaceae produce floral fatty oils in calyx glands to attract pollinating oil-collecting bees, which depend on this resource for reproduction. This specialized type of pollination system tends to be lost in members of the family that occur outside the geographic distribution (e.g. Africa) of Neotropical oil-collecting bees. This study focused on the pollination ecology, chemical ecology and reproductive biology of an oil flower species, Pterandra pyroidea (Malpighiaceae) from the Brazilian Cerrado. Populations of this species consist of plants with oil-secreting (glandular) flowers, plants with non-oil-secreting flowers (eglandular) or a mix of both plant types. This study specifically aims to clarify the role of eglandular morphs in this species.

Methods

Data on pollinators were recorded by in situ observations. Breeding system experiments were conducted by isolating inflorescences and by enzymatic reactions. Floral resources, pollen and floral oils offered by this species were analysed by staining and a combination of various spectroscopic methods.

Key Results

Eglandular flowers of P. pyroidea do not act as mimics of their oil-producing conspecifics to attract pollinators. Instead, both oil-producing and oil-free flowers depend on pollen-collecting bees for reproduction, and their main pollinators are bumble-bees. Floral oils produced by glandular flowers are less complex than those described in closely related genera.

Conclusions

Eglandular flowers represent a shift in the pollination system in which oil is being lost and pollen is becoming the main reward of P. pyroidea flowers. Pollination shifts of this kind have hitherto not been demonstrated empirically within Neotropical Malpighiaceae and this species exhibits an unusual transition from a specialized towards a generalized pollination system in an area considered the hotspot of oil-collecting bee diversity in the Neotropics. Transitions of this type provide an opportunity to study ongoing evolutionary mechanisms that promote the persistence of species previously involved in specialized mutualistic relationships.     

Evolutionary maintenance of stigma-height dimorphism in Narcissus papyraceus (Amaryllidaceae)

Stigma-height dimorphism is a sexual polymorphism in which plant populations are composed of two floral morphs that differ significantly in style length but not anther position. The morphs exhibit approach and reverse herkogamy, floral designs that in most species typically occur as monomorphic conditions. We investigated the floral biology of stigma-height dimorphism in the Mediterranean geophyte Narcissus papyraceus (Amaryllidaceae) in an effort to understand the evolutionary forces maintaining stylar polymorphism. Our survey of 66 populations in Spain, Portugal, and Morocco indicated that 56% were dimorphic with the long-styled morph at an average frequency of 0.79. The remaining 44% of populations sampled were monomorphic for the long-styled morph. In dimorphic populations there was a significant positive relation between population size and the frequency of the short-styled morph. Controlled pollinations demonstrated that N. papyraceus is self-sterile with no significant differences in female fertility between intra- and intermorph crosses. Prior self-pollination reduced seed set in flowers that were subsequently cross-pollinated. Estimates of mating patterns using allozyme markers in eight populations indicated that N. papyraceus is largely outcrossing (mean t(m) = 0.81) with no significant differences between monomorphic and dimorphic populations or style morphs. Stigma-height dimorphism in N. papyraceus is maintained in populations by insect-mediated cross-pollination with biased morph ratios and stylar monomorphism likely resulting from the combined influence of the inheritance of the polymorphism, morph-specific differences in assortative mating and founder effects.     

The pollination ecology of Paraboea rufescens (Gesneriaceae): a buzz-pollinated tropical herb with mirror-image flowers

BACKGROUND AND AIMS: Gesneriaceae is a pantropical plant family with over 3000 species. A great variety of pollination mechanisms have been reported for the neotropical members of the family, but the details of buzz-pollination and enantiostyly for the family have not been described. We investigated the floral biology and pollination ecology of Paraboea rufescens in Xishuangbanna, south-west China, considering three aspects: (1) the type of enantiostyly exhibited; (2) whether the species is self-compatible; and (3) whether pollinator behaviour could enhance the precision of pollen transfer between flowers of contrasting stylar orientation. METHODS: Flowering phenology was monitored once a month during vegetative growth, and once a week during flowering both in the field and under cultivation. Pollination manipulations and pollinator observation in the field were conducted. KEY RESULTS: Anthesis occurred early during the morning, and flowers remained open for 1-5 d, depending on weather conditions. Controlled pollinations revealed that P. rufescens is self-compatible, and exhibited inbreeding depression in seed set. Plants were pollinator limited in natural populations. The similar stylar deflection among flowers within a plant limits autonomous self-pollination as well as pollination between flowers. Two species of bumble bees (Bombus spp.), Amegila malaccensis and Nomia sp. effectively pollinated P. rufescens. These pollinators visited flowers in search of pollen with almost the same frequency. None of the pollinators appeared to discriminate between left- or right-handed flowers. CONCLUSIONS: Paraboea rufescens exhibits monomorphic enantiostylous flowers and a buzz-pollination syndrome. Floral morphology in P. rufescens and pollinator foraging behaviour seems likely to reduce self-pollination and pollinations between flowers of the same stylar deflection.     

The production of floral oils byMonttea (Scrophulariaceae) and the function of tarsal pads inCentris bees

Plant species that secrete oil as their primary floral reward are rare and sporadically found in the angiosperms. We report here thatMonttea, a genus previously unsuspected of being an oil-plant, produces lipids from trichome elaiophores on the inside of the lower (anterior) lip. The discovery of the production of oils by species of this S. American genus explains the occurrence of unusual dual-function collecting structures in ArgentineCentris (Hymenoptera: Anthophoridae) and explains the presence of oil-collecting bees in regions where oil-secreting flowers were previously thought to be absent. The behavior of these centridine pollinators onMonttea flowers parallels that of oil-collecting bees onDiascia (Scrophulariaceae) in S. Africa.     

Pollination Biology of Hosta sieboldiana (Lodd.) Engler and H. sieboldii (Paxton) J. Ingram (Liliaceae)

Abstract The pollination biology of Hosta sieboldiana and H. sieboldii is investigated comparatively in Central Japan. Both species have homogamous, one-day flowers pollinated by bumblebees. The abdomens of the bees touch the stigma on the extended style when they land on the anthers inside the herkogamous flower, and autogamy is effectively prevented. However, the flowers are fairly self-compatible, and geitonogamy may occur rather frequently because two or more flowers on a scape very often bloom at the same time and many ramets are contiguous. The pollen/ovule ratios suggest that these species are facultative outbreeders. The flower of H. sieboldii seems completely suited to bumblebee pollination. In H. sieboldiana the stigma of the flower, whose style strongly protrudes, is not always touched by bumblebees, but frequent visitation of bumblebees results in pollination of almost all the flowers. Both species have similar pollination systems but seem reproductively isolated by blooming times and habitats. Their common pollinators, however, may sometimes cause introgressive hybridization in contiguous populations.     

Homeotic, Meristic and Cytological Floral Mutants of Thryptomene calycina (family Myrtaceae)

Twenty plants with various phenotypic abnormalities to the flowerswere selected from very large populations of Thryptomene calycinain the Grampian and Black Ranges. Most of these had impairedreproductive function. Normal flowers were epigynous with fivesepals, five petals, five anthers, a single style and two anatropousovules. The mutants were two partially male sterile, tetraploidplants with large flowers, one of which occasionally producedadditional flowers from the leaf axils with peduncles as wellas pedicels; one plant which produced a proportion of hexapetaloidflowers with six stamens; three gross mutants with fleshy, bracteoidpointed petals and sepals, no stamens, vestigial styles andstigmas, exposed ovules and no inferior ovary; one plant withfleshly, bracteoid pointed sepals, vestigial style and stigmabut with exposed ovular structures replaced by four to fivesterile ovules generally inside an abnormal ovary; two plantswith reduced ovary diameter and sterile ovules, shortened style,five reduced sepals and petals and five to eight anthers; threeanthocyanin-free plants; three plants with pink sepals; twoplants with half-sized flowers which produced a proportion offasciated stems; one plant which occasionally produced flowerswithout pedicels which virtually resulted in organs which wereleaf-flower composites; two plants which produced sepals andpetals which contained chlorophyll and prematurely senesced,and had partial substitution of petals by anthers.Copyright1993, 1999 Academic Press Thryptomene calycina, Myrtaceae, Victorian lace flower, floral mutations, mutants, homeotic, meristic, tetraploid, fasciation, male sterility, cut flowers     

The Diascia (Scrophulariaceae) window: an orientation cue for oil-collecting bees

The Diascia (Scrophulariaceae) window: an orientation cue for oil-collecting beeS. Flowers of Diascia section Racemosae are characterized by an unusual translucent 'window' at the base of the upper corolla lip which is bright yellow with maroon flecks and varies from a nearly flat to a deeply cone-shaped depression. The inner epidermal cells of the window are also variable in shape ranging from lenticular to long papillate. In contrast to the surrounding corolla which strongly reflects ultraviolet light, the window tissue is strongly ultraviolet absorptive due to the presence of ultraviolet absorbing flavonoids in the epidermal cellS. Observations in natural and experimental situations suggest that the window is used as an orientation cue by oil-collecting bees.     

Stamen movements in flowers ofOpuntia (Cactaceae) favour oligolectic pollinators

Opuntia brunneogemmia andO. viridirubra occur sympatrically in the Serra do Sudeste, Rio Grande do Sul, Brazil. Their flowers have 450–600 thigmonastic stamens and provide large amounts of pollen and nectar for bees. Bees of 41 species were registered at the flowers ofO. brunneogemmia and 30 at the flowers ofO. viridirubra. Females of three oligolectic species are the only effective pollinators:Ptilothrix fructifera (Anthophoridae),Lithurgus rufiventris (Megachilidae), andCephalocolletes rugata (Colletidae). During their visits inOpuntia-flowers, bees touch the filaments and stimulate the movement of the stamens to the centre of the flower. At the end of this movement, the anthers are densely packed around the style. As a consequence the pollen is presented in an easily accessible upper layer of anthers and various, nearly inaccessible lower layers. The lower layers contain about 80% of the pollen reward. Only females of the three oligolectic pollinators exploit the pollen from the lower layers and reach the nectar furrow. Therefore, through their stamen movements,Opuntia flowers hide most of their pollen from flower visitors but favour effectively pollinating, oligolectic bees.     

Interaction between oil-collecting bees and seven species of Plantaginaceae

Oil-bee/oil-flower mutualism evolved through multiple gains and losses of the ability to produce floral oil in plants and to collect it in bees. Around 2000 plant species are known to produce floral oils that are collected by roughly 450 bee species, which use them for the construction of nests and for the larval food. The Plantaginaceae contain several Neotropical species that produce floral oils, the main reward offered by these plants. In the genera Angelonia, Basistemon, Monopera and Monttea, mainly associated with Centris bees, the floral oil is produced in trichomes that are located in the inner corolla. The pollinators of a few species in this neotropical clade of Plantaginaceae are known, and the role of flower morphology as well as the requirements from pollinators and the role of other groups of bees in the pollination of these flowers remains unclear. In this paper we provide a list of the flower visitors of seven Plantaginaceae species (six Angelonia species and Basistemon silvaticus) analyzing their behavior to highlight the legitimate pollinators and illustrating little known aspects of flower morphology and oil-collecting apparatuses of the bees. Two general morphological patterns were observed in the Angelonia flowers: deep corolla tube with short lobes, and short corolla tube with long lobes. Corolla tubes of different length result in pollen adherence to different parts of the insect body. The six Angelonia species and B. silvaticus flowers were visited by 25 oil-collecting bee species (10 Centris, 11 Tapinotaspidini and 4 Tetrapedia species), the majority acting as legitimate visitors. The flowers were also visited by illegitimate bee pollinators, which collected pollen but do not transfer it to the female organ. Specialized collectors of Plantaginaceae floral oils present modifications on the first pair of legs, mainly in the basitarsi but also extended to the tarsomeres. The new records of Tapinotaspidini and Centridini species acting as specialized pollinators of Plantaginaceae suggest that there is a geographic variation in the pollinators of the same plant species, and that the evolutionary scenario of the historical relationships between oil-collecting bees and floral oil producing plants is more complex than previously considered.     

A Remarkable Case of Ornithophily in Calceolaria: Food Bodies as Rewards for a Non-nectarivorous Bird*

In southernmost South America, the pollination biology of Calceolaria uniflora Lam. (Scrophulariaceae) was studied in the field. One of the most striking features of the flower of this species is a corolla appendage folded against the outside of the lower lip. This massive and fleshy structure is pecked off by Thinocorus rumicivorus (Thinocoridae, Charadriiformes) as a food body. The percentage of damaged flowers averaged 64% and was as high as 81% in one study site. Pollen is placed on the front of the bird's head by the exserted stamens with large versatile anthers. This pollination syndrome is unique for the bird involved and exceptional in the kind of reward offered. This Calceolaria species, and probably a second one endemic to the Falkland Islands (Islas Malvinas), are the only ornithophilous species in a mostly oil-bee pollinated genus. Their reproduction strategy appears to be adapted to an environment lacking in oil-collecting bees.