Tripleurospermum inodorum (Scentless False Mayweed)
|Also known as:||Scentless Chamomile, False Chamomile|
|Life cycle:||annual, short-lived perennial|
|Habitat:||sun; disturbed soil; roadsides, fields, dry shorelines, lawns, waste places|
|Bloom season:||May - September|
|Plant height:||8 to 32 inches|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Daisy-type flowers, single at the tips of branching stems. Flowers are 1 to 2 inches across with 10 to 25 white petals (ray flowers) and a golden yellow center disk that expands from button-shaped to dome-shaped to nearly round as it matures. The rays droop as the disk expands, bent straight down at maturity before wilting away. The disk is solid at the core.
The bracts surrounding the base of the flower are narrowly lance-oblong, darker green to brownish down the center with a narrow band of pale membranous edging but darker brown at the tip. Bracts and flower stalks are hairless, sometimes sparsely hairy when young.
Leaves and stems:
Leaves are ¾ to 3 inches long, feathery with a few to numerous thread-like branching lobes. Stems are single, erect, branched in the upper plant, weakly ridged or lined, hairless though sparsely hairy when young.
The center disk becomes a round head of dry, brown seed that lack tufts of hair. Seeds are triangular in cross-section, have 3 to 5 ribs, and a minutely textured surface between the ribs (magnification required).
Scentless False Mayweed, also known by synonyms Matricaria perforata and Tripleurospermum maritimum subsp. inodorum, is similar to the also-weedy Dog Fennel (Anthemis cotula) and Matricaria species. Dog Fennel has leaves that are pinnately lobed (divisions on opposite sides of a common stalk), have broader and flatter lobes, and a distinct, unpleasant odor when crushed. While the Maticaria species have very similar feathery and thread-like leaves, the seeds are not triangular in cross-section and are smooth between the 5 ribs. Also, Pineapple-weed (M. discoidea) lacks ray flowers, and German Chamomile (M. chamomilla a.k.a. M. recutita) has a flower disk with a hollow core and typically has multiple stems. Feel free to rip the disks open and see whether they're hollow or solid. These are all weeds, after all.
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Where to buy native seed and plants ↓
- Scentless False Mayweed plants (unmowed habitat)
- roadside Scentless False Mayweed
- Scentless False Mayweed at a boat landing with other weeds
- Scentless False Mayweed on the north shore of Lake Superior
- urban Scentless False Mayweed
- leafy upper stem
- more flowers
- German Chamomile disk is hollow, compared to Scentless False Mayweed
Photos by K. Chayka taken in Lake and St. Louis counties. Photos courtesy Peter M. Dziuk taken in Lake and St. Louis counties and in North Dakoka.
Have you seen this plant in Minnesota, or have any other comments about it?