Christian Konrad Sprengel’s Theory of the Flower: The Cradle of Floral Ecology

As the plant taxonomist Karl Suessenguth once wrote, there are two kinds of discoveries: Detecting a thing nobody has seen before, or thinking what no one has thought before about something that everybody sees. A discovery of the second kind, and one of great moments in our science, was Sprengel’s theory of the flower. This theory clearly expressed for the first time the notion that flowers are designed for the transmission of pollen by foreign vectors, that is, animals or wind, and they can be understood only from this perspective.

THE DIASCIA FLOWER AND ITS BEE - AN OIL-BASED SYMBIOSIS IN SOUTHERN AFRICA

As has been formerly shown, the double-spurred flowers of the South African genus Diascia (Scrophulariaceae) produce fatty oil as a primary attractant. Their oil-collecting pollinators have so far remained unknown. It is concluded from the morphology and from direct evidence of flower visitation that the recently established Melittid genus Rediviva represents the co-evolved pollinator group of these plants, at the same time demonstrating the presence of “manual” oil collectors in Southern Africa. The bees must introduce their especially equipped forelegs into the paired spurs of Diascia for harvesting the oil, thereby pollinating the flower. In the described case, a new species, Rediviva em…

�lproduzierende Blumen, die durch �lsammelnde Bienen best�ubt werden

Farbwechsel und Zeichnungsmuster bei Bl�ten

Pollination of four sympatric species ofAngelonia (Scrophulariaceae) by oil-collecting bees in NE. Brazil

The manner whereby the oil-producing bisaccate flowers ofAngelonia (Scrophulariaceae) are pollinated by female oil-collecting bees is reported for the first time. Observations were made in the Caatinga formation of Pernambuco, NE. Brazil, on four synchronopatric species. These differ in sizes and structural details of the corolla, level of flower exposition, and habitat preferences. All legitimate visitors wereCentris spp. (Anthophoridae):Angelonia hirta was mainly pollinated byC. fuscata andA. pubescens byC. hyptidis; A. bisaccata andA. hookeriana shared an unidentified species. Several exomalopsine, tetrapediine and meliponid bees exploit the flowers less descriminately for oil or pollen,…

A survey of the function of the lethal kettle traps of Arisaema (Araceae), with records of pollinating fungus gnats from Nepal

Abstract Evidence from recent research combined with an evaluation of the literature indicates that Arisaema is adapted to pollination by fungus gnats. It apparently shares this peculiarity among aroids only with the distantly related genus Arisarum . In addition to previous records from Japan and North America, systematic collections from nine Arisaema species during several expeditions in the Himalayas in Nepal showed that, although other less efficient insect groups may participate, the nematoceran families Mycetophilidae and Sciaridae are the principal pollen vectors; they best fit the pollination apparatus of the mainly (para)dioecious kettle trap blossoms. A total of 16 fungus gnat ge…

The perfume flowers ofCyphomandra (Solanaceae): Pollination by euglossine bees, bellows mechanism, osmophores, and volatiles

The perfume syndrome and pollination by fragrance-collecting euglossine bees in the neotropic solanaceous genusCyphomandra was confirmed by field observations. In SE Brazil,C. sciadostylis was visited byEufriesea violaceae, andC. diploconos byEuglossa mandibularis; C. hartwegii was pollinated byEulaema meriana in Costa Rica. The primary attractant, fragrant droplets that ooze from the dorsally bulged connectives, is mopped up by the males with the forebasitarsi. Thereby, the poricidal thecae are inadvertently pushed causing the dry pollen to dust the bee's sternum. The number and direction of the pollen jets are related to pollinator size and stigma structure. The flowers are homogamous, se…

Pollination: An Integrating Factor of Biocenoses

A survey is given of the ecological constraints which affect the process of pollen transfer — and hence the gene flow — within a biocenosis. Wind pollination (anemophily) plays a dominant role in species-poor communities only. The quantity of zoophilous species increases equator-ward to up to 100 % and so does the degree of integration in animal-plant interactions. Biotic pollination is pinpointed. Manifoldness and specifity of methods reduce pollen waste and mispollinations. Saturated ecosystems dispose of a complete set of pollination syndromes and the respective pollinator guilds, narrow niche widths, a high percentage of eutropic flowers, shorter flowering times, and a temporal and spat…

Bat pollination ofEncholirium glaziovii, a terrestrial bromeliad

The many-flowered, brush-like spikes ofEncholirium glaziovii, a ground-dwelling pitcairnioid bromeliad of the “campo rupestre” formation of southeastern Brazil, was observed being pollinated by the glossophagine bat,Lonchophylla bokermanni, in the Serra do Cipo (Minas Gerais). Nectar feeding was while hovering, and the pollen was preferentially transferred by the bat's snout. The floral pattern is chiropterophilous; unlike known tillandsioid bat flowers, stamens and style are protrusive beyond a small, persistent perigon, and anthesis, apparently protogynous, extends over several nights, with gradual onset and cease. Although various other flower-visitingChiroptera are known to occur in the…

Pollination neotropischer Orchideen durch duftstoff-h�selnde Prachtbienen-M�nnchen

The pollination syndrome ofDeplanchea tetraphylla (Bignoniaceae)

The reproductive structures ofDeplanchea tetraphylla (Bignoniaceae) exhibit a significant number of unusual features: inflorescence with an apical “platform”; flowers yellow, short-tubed, strongly zygomorphic; mouth closed through lateral compression; stamens and style long-exserted, erect or slightly reclined; nectar dark brown, exposed in the spoon-shaped lowermost corolla lobe and apparently acting also as a visual cue. These features suggest a highly elaborate syndrome for bird pollination: the birds (probably lorikeets) perch on the inflorescence platform and bend downwards to take up the exposed nectar, thus touching the exserted anthers and stigmas with the throat or breast. The like…