A Helianthus from Crystal in SC

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Found road side. Top/bottom of leaves very glaborous, stem hairy as well. Flowers ~1.5″-2″, 10 or more petals. May be two different species here? Color of stem is different on last photo.

Hi Crystal,

first, I think all of the images you sent are of the same species, certainly a Helianthus, one of the perennial sunflowers. However, determining it to species is very difficult without having the plant in hand. The stems are pubescent, and you say the leaves are glabrous – the upper surface in these is almost always scabrous – rough. I will give you the possibilities, and I’m sorry I cannot be definitive on the species. It could be: Helianthus decapetalus, but the stems are usually glabrous; it could be Helianthus hirsutus, but the leaves are usually more sessile, and it has rough upper leaf surfaces; it could be Helianthus divaricatus, H. tomentosus, or H. strumosus. There are even more possibilities. My opinion is that it is Helianthus divaricatus, but I cannot prove it. It needs to be run through several keys with plant in hand.


Steven Hill, Ph.D., Botanist SCNPS

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