Category: Compositae

  • White Snakeroot (Ageratina altissima)

    Photographed September 20.

    In older references this plant is Eupatorium rugosum, but the genus Eupatorium has been divided into several more manageable genera. These plants were growing at the edge of St. Michael’s Cemetery on the South Side Slopes; White Snakeroot often forms dense stands right at the border between field and forest.

    It makes bees happy.

    Here is what we wrote about White Snakeroot twelve years ago:

    One of our most decorative late-summer and autumn flowers, White Snakeroot lights up the edge of the woods and can form a perfect ornamental border around a field. Its beauty comes at a price: it’s poisonous to cattle, and the poison can be transmitted through their milk. “Milk sickness” killed Abraham Lincoln’s mother. But if you don’t have cattle, there’s no reason not to enjoy this beautiful wild native.

    As a member of the Composite family, this species is especially interesting for the way the individual little five-parted flowers are easily distinguishable in the heads. It’s a good plant for demonstrating the construction of a Composite flower to children.

    Flowers: Heads discoid (that is, with no ray flowers), in irregular flattish corymbs; flowers pure white, with protruding stamens, also white.

    Leaves. Opposite; oval, pointed, toothed, finely rough; underside with many prominent ribs; lower leaves flattish at base or almost cordate; on petioles about 1/3 the length of the leaves.

    Stem: Smooth, flexible; much branched from leaf axils; averaging about 4 feet, but quite variable and can be much taller.

  • Sneezeweed (Helenium autumnale)

    Helenium autumnale
    Photographed August 26.

    We last looked at Helenium autumnale in 2015. Since then it has become very well established in that meadow in Schenley Park. We repeat the text of the earlier article:

    Sneezeweed is an attractive composite flower with distinctively notched rays that make it easy to identify. (A similar species, Purple-Headed Sneezeweed, Helenium flexuosum, has been introduced in a few locations; it is easy to distinguish by the dark brownish button in the center.) The plant likes damp areas; this one was growing in Schenley Park, in a section of former lawn that is being allowed to grow into a meadow for better water retention. It was blooming in the middle of September.

    Habit of the plant

    Gray describes the genus and the species:

    HELÈNIUM L. SNEEZEWEED. Heads many-flowered, radiate; rays several, wedge-shaped, 3-6-cleft, fertile, rarely sterile. Involucre small, reflexed; the bracts linear or awl-shaped. Receptacle globose or ellipsoid. Achenes top-shaped, ribbed; pappus of 6-8 thin 1-nerved chaffy scales, the nerve usually extended into a bristle or point. — Erect branching herbs with alternate leaves, often sprinkled with bitter aromatic resinous globules; heads yellow, rarely purple, terminal, single or corymbed. (The Greek name of some plant, said to be named after Helenus, son of Priam.)

    Leaves broad, decurrent on the angled stem.

    H. autumnàle L. Perennial, nearly smooth, 0.2-2 m. high; leaves mostly toothed, lanceolate to ovate-oblong; heads larger (2-4 cm. broad); disk yellow; rays fertile, yellow. — Alluvial river-banks and wet ground, w. Que. and w. Mass. to Man., southw. and westw. Aug.-Oct.

    Helenium autumnale
  • Purple Coneflower (Echinacea purpurea)

    Echinacea purpurea
    Photographed July 5.

    One of our most beloved wild flowers, the Purple Coneflower is at the eastern edge of its native range here; but ornamental plantings have made it a common sight, and from those ornamental plantings come seeds that reinforce the wild population. Up close, the vivid red-orange of the disk florets is as striking as the bright pink-purple of the rays. The flower heads are very attractive to bumblebees.

    Purple Coneflower with bumblebee

    This is the Echinacea so much prized by herbalists for its supposed use against colds.

    Gray describes the genus (which he lists as Brauneria) and the species:

    BRAUNÈRIA Neck. PURPLE CONE-FLOWER. Heads many-flowered; rays mostly drooping, pistillate but sterile. Bracts of the involucre imbricated, lanceolate, spreading. Receptacle conical, the lanceolate carinate spiny-tipped chaff longer than the disk-flowers. Achenes thick, short, 4-sided; pappus a small toothed border.—Perennial herbs, with stout and nearly simple stems naked above and terminated by a single large head; leaves chiefly alternate, 3-5-nerved. Rays rather persistent; disk purplish. (Named, it is said, for Jacob Brauner, a German herbalist of the early part of the 18th century.) Echinacea Moench.

    Rays purple, rose-color, or rarely white.

    B. purpurea (DC.) Britton. Stem smooth, or in one form rough-bristly; leaves rough, often serrate; the lowest ovate, 5-nerved, veiny, long-petioled; the others ovate-lanceolate; involucre imbricated in 3-5 rows; rays 15-20, dull purple (rarely whitish), 2.5-4.5 cm. long or more. (Echinacea Moench.) — Prairies and banks, from w. Pa. and Va. to Mich., Ia., and southw.; reported as adventive eastw. July.

  • Yarrow (Achillea millefolium)

    Photographed June 22.

    Also called Milfoil, “thousand-leaf,” from the finely divided leaves. A European import that has become a common wildflower all over the East. Still a popular garden flower; in recent years many colors have been bred, but the wild ones are almost always white, or more rarely pink. The blooming season is long, from June through October. These plants were blooming just at the beginning of summer at the edge of the woods in an old German cemetery in Beechview.

    Achillea millefolium

    Gray describes the genus and the species:

    ACHILLEA [Vaill.] L. YARROW. Heads many-flowered, radiate; the rays few, fertile. Involucral bracts imbricated, with scarious margins. Receptacle chaffy, flattish. Achenes oblong, flattened, margined; pappus none. Perennial herbs, with small corymbose heads. (So named because its virtues are said to have been discovered by Achilles.)

    A. millefolium L. (COMMON Y., MILFOIL.) Stem simple or sometimes forked above, 3-10 dm. high, arachnoid or nearly smooth; stem-leaves numerous (8-15), smooth or loosely pubescent; corymbs very compound, 6-20 cm. broad, flat-topped, the branches stiff; involucre 3-5 mm. long, its bracts all pale, or in exposed situations the uppermost becoming dark-margined; rays 5-10, white to crimson, short-oblong, 1.5-2.5 mm. long. Fields and river-banks, common. (Eurasia.)

  • Ox-Eye Daisy (Leucanthemum vulgare)

    Leucanthemum vulgare
    Photographed June 3.

    Daisies are sometimes weedy invaders, but it is almost impossible to hate them. They do sometimes form dense patches and crowd out native plants; but large patches like these are relatively infrequent, and they do not seem to pose a serious danger to our ecosystem.

    A patch in Bird Park

    There is no reason not to repeat what we said ten years ago:

    This is the most universally beloved of all wild flowers, the focus of countless childhood traditions and the very image of “flower” in the popular imagination. It may be derided as a pernicious weed by agricultural and environmental authorities, but the ordinary citizen will never be persuaded to hate it.

    Daisies like these were formerly kept in the genus Chrysanthemum, but have been removed by bored botanists to the genus Leucanthemum “because they are not aromatic and their leaves lack grayish-white hairs,” according to the Wikipedia article on the genus. (The genus “Leucanthemum” was apparently named by Lamarck, whose discredited theory of inheritance of acquired characteristics still haunts high-school biology classes.) Because of this new sorting of the genera, we leave Gray and give the description of the genus and species from the Flora of North America at

    Ox-Eye Daisy
    Photographed June 19.

    Leucanthemum Miller, Gard. Dict. Abr. ed. 4. vol. 2. 1754.

    [Greek leuco-, white, and anthemon, flower]

    John L. Strother

    Perennials, (10–)40–130(–200+) cm (rhizomatous, roots usually red-tipped). Stems usually 1, erect, simple or branched, glabrous or hairy (hairs basifixed). Leaves mostly basal or basal and cauline; petiolate or sessile; blades obovate to lanceolate or linear, often 1[–2+]-pinnately lobed or toothed, ultimate margins dentate or entire, faces glabrous or sparsely hairy. Heads usually radiate, rarely discoid, borne singly or in 2s or 3s. Involucres hemispheric or broader, 12–35+ mm diam. Phyllaries persistent, 35–60+ in 3–4+ series, distinct, ovate or lance-ovate to oblanceolate, unequal, margins and apices (colorless or pale to dark brown) scarious (tips not notably dilated; abaxial faces glabrous or sparsely hairy). Receptacles convex, epaleate. Ray florets usually 13–34+, rarely 0, pistillate, fertile; corollas white (drying pinkish), laminae ovate to linear. Disc florets 120–200+, bisexual, fertile; corollas yellow, tubes ± cylindric (proximally swollen, becoming spongy in fruit), throats campanulate, lobes 5, deltate (without resin sacs). Cypselae ± columnar to obovoid, ribs ± 10, faces glabrous (pericarps with myxogenic cells on ribs and resin sacs between ribs; embryo sac development monosporic); pappi 0 (wall tissue of ray cypselae sometimes produced as coronas or auricles on some cypselae). x = 9.

    Species 20–40+ (3 in the flora): introduced; mostly temperate Europe (some widely cultivated and sparingly adventive).

    The three leucanthemums recognized here are weakly distinct and are sometimes included (with a dozen or more others) in a single, polymorphic Leucanthemum vulgare.


    Vogt, R. 1991. Die Gattung Leucanthemum (Compositae–Anthemideae) auf der Iberischen Halbinsel. Ruizia 10: 1–261.

    Leucanthemum vulgare Lamarck, Fl. Franç. 2: 137. 1779.

    Ox-eye daisy, marguerite blanche

    Chrysanthemum leucanthemum Linnaeus, Sp. Pl. 2: 888. 1753; C. leucanthemum var. pinnatifidum Lecoq & Lamotte

    Perennials, 10–30(–100+) cm. Stems simple or distally branched. Basal leaves: petioles 10–30(–120) mm, expanding into obovate to spatulate blades 12–35(–50+) × 8–20(–30) mm, margins usually pinnately lobed (lobes 3–7+) and/or irregularly toothed. Cauline leaves petiolate or sessile; blades oblanceolate or spatulate to lanceolate or linear, 30–80+ × 2–15+ mm, margins of mid-stem leaves usually irregularly toothed proximally and distally.Involucres 12–20+ mm diam. Phyllaries (the larger) 2–3 mm wide. Ray florets usually 13–34+, rarely 0; laminae 12–20(–35+) mm. Ray cypselae 1.5–2.5 mm, apices usually coronate or auriculate. 2n = 18, 36, 54, 72, 90.

    Flowering spring–fall. Disturbed places, meadows, seeps, clearings; 0–2000 m; introduced; Alta., B.C., Ont., Que., Sask.; Alaska, Ariz., Ark., Calif., Colo., Conn., Fla., Idaho, Ill., Ind., Iowa, Kans., Mass., Mich., Mo., Mont., Nev., N.Mex., N.Y., N.Dak., Ohio, Okla., Oreg., Pa., S.C., S.Dak., Tenn., Utah, Va., Wash., W.Va., Wis., Wyo.; Europe, widely adventive.

    Some botanists (e.g., W. J. Cody 1996) have treated Leucanthemum ircutianum de Candolle, with blades of mid and distal cauline leaves oblong to oblong-lanceolate and not ± pinnate at bases, as distinct from L. vulgare.

    A patch in Bird Park
    In Castle Shannon