Friday, November 13, 2009

Wetland Plant of the Week #32

Aster carolinianus

Climbing Aster

Climbing aster, unlike the majority of the other varieties in the genus (which are herbaceous), presents as a many branched shrub with a woody stem base and often even woody branches. The Obligate plant displays numerous leaves that range from elliptic to lanceolate in shape. The flowers are typically about an inch in diameter and generally have a light-blue or light-purple color.

Aster carolinianus is native to the coastal plain of the southeastern United States and is often found residing in marshes, along stream banks and - as pictured above - in freshwater swamps.

As a characteristic trait, the climbing aster has the habit of entangling itself in the branches of surrounding plants, or even tying itself in large tousled masses.

Asterales, the order to which the Asteraceae family belongs, has origins in the Cretaceous period about 100 million years ago and probably experienced diversification during the Oligocene and Miocene. In regards to their evolutionary past, recent research by Tom Viaene (et al) examined the variability of stamen and petal morphologies within the basal asterid families. Through comparisons of the genes that coded for these floral structures, he determined that the early members of the asterid group likely duplicated the petal and stamen genes as a strategy for moving into a wider range of niches.

The above images were taken last week near St. Marks National Wildlife Refuge in northern Florida.

Viaene, T., Vekemans, D., Irish, V., Geeraerts, A., Huysmans, S., Janssens, S., Smets, E., & Geuten, K. (2009). Pistillata--Duplications as a Mode for Floral Diversification in (Basal) Asterids Molecular Biology and Evolution, 26 (11), 2627-2645 DOI: 10.1093/molbev/msp181

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