Tripleurospermum inodorum (Scentless False Mayweed)

Plant Info
Also known as: Scentless Chamomile, False Chamomile
Genus:Tripleurospermum
Family:Asteraceae (Aster)
Life cycle:annual, short-lived perennial
Origin:Europe
Status:
  • Weedy
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):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: 7+petals Cluster type: panicle

[photo of flowers] 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.

[photo of bracts] 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: Leaf attachment: alternate Leaf type: compound Leaf type: lobed

[photo of leaves] 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.

Fruit: Fruit type: seed without plume

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).

Notes:

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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More photos

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.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Duane Madison - McQuade Rd, Duluth, MN (5 mi. N of Lake Superior
on: 2018-07-23 09:14:45

In my area I have seen Tripleurospermum inodorum only twice and both times on land I had just opened up and hadn't seeded for lawn yet. The first one, about 5 years ago, disappeared after mowing. The second one was this spring and quite far (500')from the first location. As a young plants, before blossoming, they were extremely and beautifully plumey at a height of about 18 inches before blossoming. For that reason I plan on preserving seed for propagating. I realize it is noxious in one or two states but that seems extreme for a plant that is easily eliminated with mowing. Even now, in full blossom, it is very showy. Duane (real men can like flowers) Madison

Posted by: Barb - Proctor
on: 2019-07-20 09:50:55

July 20. I have a large plant growing in a dirt pile The plants are approximately 24-30" high. Very pretty and loaded with flower heads.

Posted by: gary - Carlton
on: 2019-10-22 19:20:12

This species came in, as seeds I suppose, with some compost from the eastern part of the county. It persisted for many years in one area until the grass got too thick. It does show up in my vegetable gardens occasionally.

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