Tuesday, August 14, 2012

Woodland Sunflower

This attractive composite is very common in Black Oak savannas that are not too shady from fire suppression. It is colonial by elongate rhizomes and its colonies are sometimes quite dense. Like the cultivated sunflower, it is common to see all flowers in a colony facing the same way. This plant sometimes shows up in other types of woodland. Photographed at the Heinze Land Trust's Coulter Preserve in Porter County, Indiana. (Helianthus = sun flower). 

It is a very good idea to use botanical keys and descriptions when identifying wild sunflowers. The trouble with a close-up photo is that the plant's distinctive features often do not show up in the picture. Here is another shot of the same plant shown above, with the following features visible (from the Gleason & Cronquist description)  -stems glabrous below the inflorescence, often glaucous; leaves all opposite, sessile or rarely on a petiole to 5 mm, scabrous above, narrowly lanceolate to broadly lance-ovate, broadest near the truncate or broadly rounded base, tapering to the slender, acuminate tip, shallowly toothed or subentire, trinerved near the base; heads 1-several at the tips of stiff, cymose branches; disc yellow, involucral bracts lance-acuminate or -attenuate; ciliolate, often with deflexed tips (I don't see that, but "often" doesn't mean "always").  I believe it is Woodland Sunflower, Helianthus divaricatus


Scott Namestnik said...

H. divaricatus?

Keith Board said...

Yes, see added comments between the two photos.