Achillea millefolium L.

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Achillea millefolium plant

Family - Asteraceae

Habit - Rhizomatous perennial forb.

Stems - Erect, to 80 cm, herbaceous, densely wooly-pubescent, branching in upper half, erect, fragrant when crushed.

Achillea millefolium stemStem close-up.

Leaves - Alternate, sessile, linear to lanceolate or oblong, twice or ternately pinnatifid, pubescent with wooly hairs. Basal leaves to 25 cm long. Cauline leaves typically to 10 cm long, 3 cm broad.

Achillea millefolium leaf Achillea millefolium leaf
Basal and stem leaves.

Inflorescence - Flat or domed terminal cymose arrangement of flower heads.

Achillea millefolium inflorescenceInflorescences.

Involucre - 5mm tall(long), 3mm in diameter. Phyllaries in 2-3 series, with scarious margins, lanate pubescent, imbricate. Outer phyllaries shorter than inner.

Achillea millefolium involucreInvolucre(s) close-up.

Ray flowers - Ligules typically 5 per flower head, white to pinkish, 5mm long, clawed. Expanded portion of ligule 3mm long, 2-3mm broad, emarginate or shallow 3-toothed at apex. Claw 2mm long, greenish, glandular. Achene flattened. Pappus none.

Disk flowers - Disk to 3mm in diameter. Flowers typically 5-20 per flower head, fertile. Corolla tube to -2mm long, greenish, 5-lobed. Lobes white. Achenes flattened. Pappus none. Receptacle slightly convex, with chaff equaling disk flowers.

Achillea millefolium flowersFlowers close-up.

Fruits - Achenes 1-2 mm long, oblong-obovate, flattened, broadly rounded to nearly truncate at the tip, the margins somewhat thinner and sometimes appearing as blunt wings, the surface smooth, glabrous, tan to light brown with lighter margins.

Flowering - May - November.

Habitat - Roadsides, railroads, disturbed sites, pastures, fields, prairies.

Origin - Native to the U.S. and Europe.

Other info. - Foliage of this plant is strongly aromatic when bruised or crushed. Although Yatskievych asserts that the odor is unpleasant, this is a judgement call, and indeed the plant and others in the same genus have been used to brew herbal teas. The plant has been called "nosebleed," presumably for a putative ability to initiate nosebleeds. Steyermark tested this hypothesis by stuffing the foliage up his nostrils, and reported that A. millefolium caused no irritating or burning sensation and thus was ineffective for this purpose.

Although Steyermark and other authors have subdivided the species, the situation is complex with a confusing jumble of character states and ploidy levels which are inconsistent and do not correlate well. More research on this complex is needed. There are also numerous horticultural cultivars of Achillea, as shown below. One yellow flowered plant is named Achillea Moonshine.

Achillea moonshine plant Achillea purple cultivar

Photographs taken at Hermes Nursery, Kansas City, Kansas, 07-14-00, and in the Ozark Scenic Riverways, Shannon County, MO., 5-24-03 and 6-16-05 (DETenaglia); also at Matson Hill County Park, St. Charles County, MO, 5-17-2012, and at Shaw Nature Reserve, Franklin County, MO, 5-27-2015 (SRTurner).

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