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14.1: Pollination Syndromes

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    Flowers have coevolved with their pollinators. The shape, color, smell, and many other features of a floral phenotype are adapted to their method of pollen dispersal. This set of characteristics is called a pollination syndrome and allows scientists to make inferences about the pollinator of a particular flower. Some of these are more obvious, while others, more cryptic. For example, humans do not see ultraviolet (UV) light, but many insects can (like bees). Flowers might be communicating with UV light in a way that might not be apparent to humans until you shine a UV light on them. In the Malva assurgentiflora flower (Figure \(\PageIndex{1}\)), the pollen has UV fluorescence.

    A Malva assurgentiflora flower viewed in normal light. The petals appear a fuschia pink and the pollen looks whitish.
    The same Malva assurgentiflora flower, the petals appear a dark blackish purple and the pollen glows a neon blue.
    Figure \(\PageIndex{1}\): A Malva assurgentiflora flower in regular light (first photo) and ultraviolet light (second photo). In the first photo, the pollen looks a dull white and the petals are a vibrant fuschia pink. In the second photo, the petals appear dark burgundy purple, while the pollen is a glowing neon blue. The pollen of this flower has UV fluorescence; when the pollen absorbs UV light, it emits it at a different frequency and appears to glow. Photos by Alan Rockefeller, CC-BY-SA.

    Pollination Syndromes and Vectors

    Though flower phenotypes can also correlate to other environmental factors (e.g. Peach et al. 2020), we can connect pollination syndromes to pollen vectors, both biotic and abiotic (see Table \(\PageIndex{1}\)).

    Table \(\PageIndex{1}\): Pollination Syndromes (adapted from the US Forest Service).
    Pollination Syndrome




    Nectar or Pollen


    Dull, perianth often absent or reduced

    Large feathery stigmas, large anthers


    No nectar, large amounts of pollen


    Reds and pinks

    Often tubular or cupped


    Lots of hidden nectar, moderate pollen


    Purples, blues, yellows, white, UV

    Flat and shallow or tubular, with landing area

    Sweet, fresh, mild

    Pollen often sticky and scented, nectar usually present


    White, dull green, or purple

    Often bowl-shaped or pendant, anthers protruding

    Musty or fruity, strong, emitted at night

    Lots of hidden nectar


    White, pale pink or purple

    Often tubular or cupped, no landing pad

    Strong and sweet, emitted at night

    Lots of hidden nectar, limited pollen


    Bright colors

    Tubular, with wide landing pad

    Faint, fresh

    Lots of hidden nectar, limited pollen


    Dark red, purple, brown

    Shallow, funnel, or trap-like

    Putrid, rotting

    No nectar, moderate pollen

    Two Trillium flowers of the same species. The one on the left is purple, while the one on the right is white.
    Figure \(\PageIndex{2}\): Trillium ovatum flowers are white until they have been pollinated, at which point they begin to turn pinkish-purple. In the image above, the flower on the left has been pollinated, while the one on the right has not. Photo by Maria Morrow, CC-BY 4.0.

    Examples of Pollination Syndrome Characteristics

    Bees, Bee-Like Flies, and Butterflies

    This dandelion is yellow with a surface for an insect to land on.
    Figure \(\PageIndex{3}\): The yellow color and surface for an insect to land and crawl around on in this head inflorescence are characteristic of bee pollination. However, this flower does not smell particularly fresh or sweet. Instead, the odor is more astringent and a bit unpleasant. Photo by Maria Morrow, CC-BY 4.0.
    A foxglove inflorescence with bell-shaped, purple flowers. The entrance to the flower has a speckled landing pad.
    Figure \(\PageIndex{4}\): These foxglove florets are purple and bell-shaped. The lower petal serves as a landing pad for bees, with a speckled pathway (nectar guide) to lead the bee to the nectar at the center of the flower. The anthers are visible on the lowest full floret, dangling above the entrance to deposit pollen on the bee's back as it crawls in. Photo by Maria Morrow, CC-BY 4.0.
    A purple and yellow Iris flower with nectar guides to lead the bee to the center of the flower.
    Figure \(\PageIndex{5}\): This Iris flower has a bee pollination syndrome. The primary colors are purple and yellow. There are nectar guides leading the bee to the center of the flower. To get there, the bee must crawl under the stigma first, then under the anthers. This flower has a pleasant, sweet smell. Photo by Maria Morrow, CC-BY 4.0.
    Purple flowers with a lip to land on and a hooded area to crawl into. Behind this entrance, a long tubular next spur extends.
    Figure \(\PageIndex{6}\): This Delphinium flower has a butterfly pollination syndrome (this also works for long-tongued bees). The color is purple, there is a lipped petal that serves as a landing pad, and there is a long nectar spur extending from the back of the flower. This flower has a pleasant, sweet smell. Photo by Maria Morrow, CC-BY 4.0.


    A dangling Fuschia flower with a pink calyx and purple corolla.
    A cluster of Castilleja flowers pointing upright
    Figure \(\PageIndex{7}\): These flowers have a bird pollination syndrome. The Fuschia (left) is pink and purple, pendant, and relatively odorless. The nectar is located deep within the flower at the base of a hypanthium. The Castilleja (right) is bright red with many tubular flowers (these could also be butterfly pollinated). First image by Peter Clarke, CC BY-SA 3.0 via Wikimedia Commons. Second image by Maria Morrow, CC-BY 4.0.
    A bird with a long bill hovers in front of red, tubular flowers with long anthers and styles.
    Figure \(\PageIndex{8}\): A hummingbird pollinating red, tubular flowers. The anthers and stigma extend below where the hummingbird enters, rubbing it on the chin and chest when it goes in for nectar. Photo by VJAnderson, CC BY-SA 4.0 via Wikimedia Commons.

    Flies and Beetles

    A Fritillaria flower, which is a large pendant flower. The petals are greenish and speckled with red.
    Figure \(\PageIndex{9}\): Fritillaria flowers are often fly pollinated. The dark red splotches on the petals and overall unpleasant smell fit a fly pollination syndrome. Check out this page to see Fritillaria species being pollinated by flies. Photo by Maria Morrow, CC-BY 4.0.
    A cluster of small white and green florets with a beetle on top of them
    A large, open, white flower (Magnolia)
    Figure \(\PageIndex{10}\): These flowers have a beetle pollination syndrome. Beetles prefer white to green flowers with a large place to land. First image from Pollinator at the English language Wikipedia, CC BY-SA 3.0 via Wikimedia Commons. Second image by Sweetbay_Magnolia_Magnolia_virginiana_Flower_Closeup_2242px.jpg: Photo by and (c)2008 Derek Ramsey (Ram-Man). Co-attribution must be given to the Chanticleer Garden.derivative work: Bff, CC BY-SA 3.0 via Wikimedia Commons.


    A grass inflorescence with large dangling anthers and feathery stigmas. No showy floral parts or colors are present.
    Figure \(\PageIndex{11}\): Wind pollinated flowers have a reduced or absent perianth, large anthers, and feathery stigmas. This grass spike has large pinkish anthers dangling from long filaments. Feathery stigmas can be seen emerging from some of the florets. Photo by Maria Morrow, CC-BY 4.0.

    This page titled 14.1: Pollination Syndromes is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Maria Morrow (ASCCC Open Educational Resources Initiative) .

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