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8.4: Inflorescence Types

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    Spathe & Spadix

    The spathe of a Calla lily The top of a Calla lily spadix
    Figure \(\PageIndex{1}\): In the image on the left, the spathe is shown wrapped around and enclosing the spadix (not visible). The spathe on a Calla lily looks like one large, funnel-shaped, white petal. In the image on the right, the top of the spadix is shown. This part of the spadix is covered with the male florets, making pollen. Photos by Maria Morrow, CC BY-NC.
    The base of a Calla lily spadix
    Figure \(\PageIndex{2}\): This is the base of the Calla lily spadix. It is covered with female florets. The gynoecium is shaped like a bowling pin, each with a large knob-like stigma at the top. Photo by Maria Morrow, CC BY-NC.

    Head (also called a composite or capitulum)

    Head inflorescence with pollinators
    Figure \(\PageIndex{3}\): A dandelion head inflorescence. Each "petal" is actually composed of five fused petals of a single floret. The tube-like structures emerging upward are the styles, each with two curled stigma lobes. Because this inflorescence has no disc flowers, it is called a ligulate head. Photo by Maria Morrow, CC BY-NC.
    A head inflorescence with two floret types The phyllaries of the head inflorescence in the previous picture
    Figure \(\PageIndex{4}\): This oxeye daisy has a head inflorescence with two types of florets. In the center, there are yellow disc florets. These have five short petals and radial symmetry. Lining the outside of the inflorescence are white ray florets. These have several petals fused together in one long strap-like, bilaterally symmetrical corolla. The image on the right shows the bracts lining the outside of the inflorescence, called phyllaries. People commonly mistake these as sepals when considering this inflorescence as a single flower. Photos by Maria Morrow, CC BY-NC.
    A clover head inflorescence
    Figure \(\PageIndex{5}\): Clovers are quite beautiful, particularly up close. The fuzzy ball it produces is composed of many bilaterally symmetrical florets, typical of the flower morphology found in the legume family. These florets all attach to the same receptacle. Can you locate the calyx and corolla of each floret? Photo by Maria Morrow, CC BY-NC.


    A Plantago inflorescence
    Figure \(\PageIndex{6}\): This Plantago inflorescence is a wind-pollinated spike. The florets have no showy perianth. The prominent structures seen here are the large anthers, located at the end of long, thin filaments. These florets are sessile, attached directly to the peduncle with no pedicels. Photos by Maria Morrow, CC BY-NC.


    A pendant raceme of Wisteria florets
    Figure \(\PageIndex{7}\): This Wisteria inflorescence is a pendant raceme. The florets are each attached to the peduncle by a short stem called a pedicel. One of these is indicated in the image with a white arrow. Wisteria is also in the legume family. Can you see the similarity between these florets and the ones in the clover inflorescence in Figure \(\PageIndex{5}\)? Photo by Maria Morrow, CC BY-NC.


    Willow female catkins Willow male catkins
    Figure \(\PageIndex{8}\): Willows produce catkins. In the first image, there are several female catkins. There is no showy perianth or androecium, just a large gynoecium for each floret, giving the appearance of a spiky stick. In the second image, there is an androecium instead of a gynoecium. The yellow anthers are held out on thin filaments, making these male catkins look like yellow, fuzzy caterpillars. Photos by Maria Morrow, CC BY-NC.


    An umbel, where the pecidels attach to a single point and end in florets A green peduncle transitions into a spray of smaller pedicels, each with a purple floret at the end.
    Figure \(\PageIndex{9}\): In an umbel, the pedicels all emerge from the top of the peduncle. The Allium cernuum inflorescence on the right is a drooping umbel. Drawing by Pearson Scott Foresman, Public domain, via Wikimedia Commons. Photo on the right by Steve Ganley, CC-BY-NC.
    An umbel inflorescence where each pedicel has its own umbo of tiny white florets
    Figure \(\PageIndex{10}\): A compound umbel is when each pedicel then forms its own umbel. Drawing by H.M. Dixon, Public domain, via Wikimedia Commons. Photo of Aegopodium podagraria by Сергей, CC-BY-NC.

    This page titled 8.4: Inflorescence Types 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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