Status: Native
Synonyms:
Helianthus aridus Rydberg
Helianthus annuus is a tall annual roadside sunflower. For the size of plant,
it pulls out of the ground readily. The disc is purple-brown, and the rays are yellow. The
phyllaries are ciliate on the margin and ovate. The phyllaries of Helianthus petiolaris are
lanceolate and their margins have shorter, more bristly hairs. The achenes are glabrate.
The stem cross section demonstrates the typical vascular ring of phloem and xylem of most eudicots.
Please click on an image for a larger file.
Helianthus annuus, photo Russ Kleinman & Karen Blisard, Burro Mtns., Tyrone-Thompson Road, June 13, 2007
Helianthus annuus, growth habit, photo Russ Kleinman & Karen Blisard, Burro Mtns., Tyrone-Thompson Road, June 13, 2007
Helianthus annuus, ovate and ciliate phyllaries, photo Russ Kleinman, Burro Mtns., Mangus Springs, July 1, 2009
Helianthus annuus, photomicrograph of stem cross section, photo Russ Kleinman & Karen Blisard, Pinos Altos, July 18, 2022
Helianthus annuus, photomicrograph of root cross section (stained with crystal violet), photo Russ Kleinman & Karen Blisard, Pinos Altos, October 9, 2022
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