Summary ⁵

Helenium amarum is a species of annual herb in the daisy family known by the common names yellowdicks, yellow sneezeweed, fiveleaf sneezeweed, and bitter sneezeweed. It is native to much of the south-central United States (Texas, Oklahoma, Louisiana, Arkansas, New Mexico) and northern Mexico (Chihuahua, Coahuila), and it is present elsewhere in North America, Australia, and the West Indies as an introduced species.

Comments ⁶

This is one of many wildflowers in the Aster family that produces showy yellow flowerheads during the summer and fall. Like other species in its genus, the flowerheads of Bitterweed have very distinctive petal-like rays with broad 3-toothed tips. Bitterweed is also distinguished by its very narrow leaves (less than 1/8" across) that are nearly filiform; they often occur in short clusters along the stems. Other Helenium spp. in Illinois have wider leaves and they prefer habitats that are more damp.

Description ⁷

This wildflower is a summer annual about ½-2½' tall. A robust plant is unbranched below and abundantly branched above; the stems are light green and hairless (or nearly so). Abundant alternate leaves are located along these stems; they are widely spreading to ascending. Individual leaves are ½-3" and less than 1/8" across; they are simple (non-compound), linear-filiform, sessile, and smooth along their margins. Frequently, these narrow leaves often occur in short axillary clusters (making them appear whorled or palmately lobed); they are light to medium green or grayish blue, glandular-dotted, and hairless (or nearly so). Flowerheads about ¾" across occur individually on erect peduncles about 1-5" long. Each flowerhead has 5-10 ray florets surrounding numerous tiny disk florets (75 or more); both types of florets are yellow. The petal-like rays become wider toward their tips, where they are 3-toothed; their florets are pistillate and fertile. The disk florets have tubular corollas with 5 tiny teeth along their upper rims; they are perfect and fertile. At the base of each flowerhead, there are several linear-lanceolate bracts (phyllaries) that are light green; they extend downward while the flowerhead is blooming. The blooming period occurs from late summer into the fall and lasts 1½-3 months. Both the disk and ray florets are replaced by small achenes (about 1-1.25 mm. in length) that are reddish brown, oblanceoloid, angular, and hairy. Each achene has a crown of several awned scales at its apex. The root system consists of a short branching taproot. This wildflower spreads into new areas by reseeding itself.

Sources and Credits

1. (c) Jerry Oldenettel, some rights reserved (CC BY-NC-SA), http://www.flickr.com/photos/7457894@N04/3618410222
2. (c) Jeff Forman, some rights reserved (CC BY-NC), uploaded by Jeff Forman
3. (c) Jerry Oldenettel, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/jroldenettel/36114959716/
4. (c) Lena Zappia, some rights reserved (CC BY-NC), uploaded by Lena Zappia
5. Adapted by Amber Leung from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Helenium_amarum
6. (c) John Hilty, some rights reserved (CC BY-NC), http://eol.org/data_objects/29586481
7. (c) John Hilty, some rights reserved (CC BY-NC), http://eol.org/data_objects/29442009

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