Abstract Detail

Anatomy and Morphology

Loll, Jessica [1], Garcia, Antonio [1], Gardner, Andrew [1].

Applying geometric morphometrics to explore floral shape evolution in Downingia.

The 15 species of calicoflowers (Downingia) are found primarily in California. Many of the species are endemic to vernal pools, which display a field of color as their waters recede each year. Downingia flowers encompass a wide range of shapes and color patterns that may reflect diverse pollinator preferences. Recently described cryptic species and prior evidence of complex evolutionary processes has inspired us to to characterize flower shape via geometric morphometrics as a way to further study their evolution. We are developing 2D floral shape models from both head-on and side-view floral images from publicly available repositories and our own field images. Whereas head-on view images are biologically relevant and widely available, we are also using side-views to better characterize the depths of the floral structures such as the anther tubes and staminal columns. For each view, we selected a series of landmarks that can be unambiguously positioned on every image. After a transformation that removes scale and rotation, we use principal component analysis to describe variation among the images’ landmarks. In both of these initial datasets, Downingia species are relatively cohesive in terms of floral shape. The highly variable dorsal petals account for a large portion of the overall variation, and their exclusion has a major impact on the interpretability of the models generated. Taken together, the models largely reinforce the suite of co-varying characteristics that distinguish the previously described floral shape categories. We will continue to improve our models as we incorporate more images. Well-developed shape models will help us to better interpret evolutionary processes that may influence floral shape, such as pollination shifts and hybridization.

1 - CSU Stanislaus, One University Circle, Turlock, CA, 95382, United States

geometric morphometrics

Presentation Type: Poster
Number: PAM013
Abstract ID:667
Candidate for Awards:None

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