Fig 182. [May-weed. Dog's-Fennel. Anthemis Cotula] L.
![[May-weed. Dog's-Fennel. Anthemis Cotula]](#1525880611323293367_fig-182.jpg.id-6588476871511922158.wrap-0.html.html){kind=link}
May-weed. Dog's-Fennel. Anthemis Cotula L. Outer flowers white; achenes straw color to light brown, obovoid (large end uppermost) to oblong, circular in outline, 1.3–1.8 mm. long, with 10 warty ribs. Introduced from Europe. Old roads and waste places.
Fig 183. [Great Burdock. Arctium Lappa.]
![[Great Burdock. Arctium Lappa.]](#1525880611323293367_fig-183.jpg.id-5537714022899983859.wrap-0.html.html){kind=link}
Great Burdock. Arctium Lappa. So far as I have seen the achenes of this species, when compared with A. minus, are darker colored, rather longer, the ribs more distinct.
Smaller Burdock. Arctium minus Beruh. Possibly only a variety of A. Lappa L., but the prevailing plant in central Michigan. I see no way of distinguishing the achenes of one from the other; but it makes little difference as one burdock is as bad as another.
Flowers purple; achenes dull brown, often spotted with black, straight or curved, slightly flattened, oblong-prismatic with 3–5 narrowly ridged angles, and occasionally other smaller ridges, 4.5–6 mm. long. Introduced from Europe.