common nipplewort

Common nipplewort, also called simply nipplewort, is an exotic, weedy, easily recognized, flowering plant. It is native to Europe, western Asia, northern Africa, and the Indian subcontinent. It was introduced in many regions and is now naturalized widely, including in North America. It occurs in the United States in the east from Maine to northern Georgia, west to Minnesota and Arkansas. In the west it occurs in northern Washington, west to Idaho, and south to southern California. Outside of these areas, it has also been reported in most major metropolitan areas except in the Southwest, the Great Basin, and the Great Plains.

In regions outside of its native range, common nipplewort is found in disturbed areas, including woodland openings, fields, forest edges, stream banks, roadsides, city alleys, campgrounds, edges of yards, and gardens. It grows under full sun to light shade, in moist to dry, loamy or gravelly soil. Once established, it is difficult to eradicate. It can survive infrequent or irregular mowing, and the seeds remain viable in the soil for up to five years.

Common nipplewort is an erect, annual forb that rises on usually a single stem, sometimes a few stems, from shallow, fibrous roots. It can be 6″ to 60″ (15 to 150 cm) tall, but it is usually no more than 32″ (80 cm) in height.

The stem is erect, green or often reddish, round, and finely ridged. It is sparsely to moderately covered at first with slender, spreading hairs. The hairs near the tip are often gland-tipped. The stem sometimes becomes almost hairless as it ages. It is unbranched or it has only a few branches below the inflorescence.

Both basal and stem leaves are produced. The basal leaves are few and do not form a rosette. The stem leaves are alternate. Basal and lower stem leaves are up to 6″ (15 cm) long and up to 2¾″ (7 cm) wide. They are on long, narrowlywinged leaf stalks (petioles). The leaf blade is inversely egg shaped to inversely lance shaped in outline. It is deeply, pinnately cut into usually three, sometimes more lobes. The terminal lobe is large and egg shaped to broadly triangular. The lateral lobes are much smaller and sharply triangular. The shape resembles a nipple, and this is the source of the common name of this plant. The spaces between the lobes (sinuses) are broadly rounded. The upper and lower surfaces are sparsely to moderately covered with short, white, more or less spreading, non-glandular hairs. The margins are scalloped and wavy. There is a single main vein, several secondary veins extending outward then branching and rejoining before reaching the margin (anastomosing), and a network of tertiary veins. The veins are depressed, and they give the leaf surface a wrinkled appearance.

The inflorescence is a branched, open, flat-topped, rounded, egg-shaped, or cylinder-shaped array (panicle) of usually 15 to 25, sometimes many more, flower heads. Each flower head is on a long, slender stalk (peduncle). The peduncle is hairless, and it has no inflorescence leaves (bracts). Beneath each flower head there is a group (calyx) of 4 to 5 bracts (calyculi). Each calyculi is hairless, scale-like, and 1⁄64″ to 1⁄16″ (0.5 to 2.0 mm) long. Surrounding the base of the flower head is a whorl (involucre) of 8 or 10 bracts (phyllaries). The phyllaries are stiff, erect, hairless, linear oblong, and of equal length ⅛″ to ⅜″ (3 to 9 mm) long.

Each flower is ½″ (12 mm) in diameter. There are 8 to 15 pale yellow to lemon yellow ray florets and no disk florets. Each ray floret is strap shaped, is ¼″ to ⅜″ (7 to 10 mm) long, and has 5 teeth at the tip.

The fruit is a tan to golden brown, ⅛″ to 3 ⁄16″ (3 to 5 mm) long, curved seed capsule (cypsela) with a single seed. The outer cypselae are much longer than the inner ones. Each cypsela is hairless and has about 20 ribs. There is no tuft of hairs (pappus) at the tip.

6″ to 60″ (15 to 150 cm)

Yellow

Moist to dry. Full to partial sun. Disturbed areas, including woodland openings, fields, forest edges, stream banks, roadsides, city alleys, campgrounds, edges of yards, and gardens. Loamy or gravelly soil.

Junie to September

Sources

2, 3, 4, 5, 22, 24, 28, 29, 30.

MISIN. 2024. Midwest Invasive Species Information Network. Michigan State University – Department of Entomology. USA. http://www.misin.msu.edu. Accessed 10 September, 2024.

Native to Europe, western Asia, northern Africa, and the Indian subcontinent. Introduced and naturalized.

Several subspecies have been described in Europe. Only one has been introduced in North America. Where only one subspecies occurs on the continent, most North American sources do not list the subspecies (trinomial) name, just the species (binomial) name.

This has quickly spread throughout a no mow area. Fearing another invasive. Difficult to get a clear photo of the cluster of tiNY flowers on top.

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Location: Lake Shore

This has quickly spread throughout a no mow area. Fearing another invasive. Difficult to get a clear photo of the cluster of tiNY flowers on top.