Now classified as Ageratina altissima by most botanists, the genus Eupatorium having been broken up into a number of smaller concerns by the FTC.

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. These plants grew at the edge of the woods in Mount Lebanon, where they were blooming in the middle of September.

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.

Gray lists this plant as Eupatorium urticaefolium:

EUPATÒRIUM [Tourn.] L. THOROUGHWORT. Heads discoid, 3-many-flowered; flowers perfect. Involucre cylindrical or bell-shaped, of more than 4 bracts. Receptacle flat or conical, naked. Corolla 6-toothed. Achenes 6-angled ; pappus a single row of slender capillary barely roughish bristles. — Erect perennial herbs, often sprinkled with hitter resinous dots, with generally corymbose heads of white, bluish, or purple blossoms, appearing near the close of summer. (Dedicated to Eupator Mithridates, who is said to have used a species of the genus in medicine.)

1. EUPATORIÜM proper. Receptacle flat.

Heads 5-30-flowered; involucral brada nearly equal, in one row or but a very few of the outermost shorter; leaves opposite, ovate, petioled, triple-nerved, not resinous-dotted.

Leaves broadly ovate; flowers pure white.

E. urticaefòlium Reichard. (WHITE SNAKEROOT.) Smooth, branching, 0.5-1 m high; leaves broadly ovate, pointed, coarsely and sharply toothed, long-petioled, thin, 7-12 cm. long; corymbs compound. (E. ageratoides L. f.) — Rich woods, not rare. Var. villicaúle Fernald. Stems and petioles viscidvillous. — Pa. (Heller) to Va. (Curtías).

“Tall” is just the word we were looking for to describe this plant, which grew to at least twelve feet (4 m) in a clearing in the woods in Beechview. It was blooming in the middle of September. This is indeed a close relative of the garden Lettuce (L.sativa). The generic name, an old Latin word from which the common name is derived, refers to the milky white sap.

Gray describes the genus and the species, which he lists as L. spicata:

LACTÙCA [Tourn.] L. LETTUCE. Heads several-many-flowered. Involucre cylindrical or in fruit conical; bracts imbricated in 2 or more sets of unequal lengths. Achenes contracted into a beak, which is dilated at the apex, bearing a copious and fugacious vегу soft capillary pappus, its bristles falling separately. — Leafy-stemmed herbs, with panicled heads; flowers of variable color, produced in summer and autumn. (The ancient name of the Lettuce, L. sativa L.; from lac, milk, in allusion to the milky juice.)

§ 3. MULGÈDIUM (Cass.) Gray. Achenes thickish, oblong, contracted into a short thick beak or neck; annual or biennial; flowers chiefly blue.

Pappus tawny.

L. spicàta (Lam.) Hitchc. Nearly smooth biennial, tall (1-3.6 m. high), very leafy; leaves irregularly pinnatifid, sometimes runcinate, coarsely toothed, the upper cauline sessile and auriculate, sometimes clasping; heads in a large and dense compound panicle; flowers bluish to cream-color; achene short-beaked. (L. leucophoea Gray. ) — Low grounds, rather common.

A heaping helping of ragweed, easily growing to 9 feet (3 m) if it likes the location (Gray says to 6 m or 18 feet), and letting loose a raging torrent of allergenic pollen in early September, as these plants in Beechview were doing. The harmless and beautiful goldenrods that bloom at the same time often take the blame for hay fever, but this huge yet somehow inconspicuous weed, and its even more common little cousin A. artemisiifolia, are the real culprits. These plants appear to be what Gray describes as the variety integrifolia: the leaves are mostly three-lobed, except for a few unlobed lanceolate leaves up near the flowers.

The generic name Ambrosia, from the Greek word for “immortal,” probably means that, as weeds go, these things are hard to kill. It was probably not intended to suggest that the Olympian gods supped on ragweed.

Gray describes the genus and the species:

AMBRÒSIA [Tourn.] L. RAGWEED. Fertile heads 1-3 together, sessile in axils of leaves or bracts, at the base of racemes or spikes of sterile heads, Merile involucres flattish or top-shaped, of 7-12 united bracts, containing 6-20 staminate flowers, with or without slender chaff intermixed. Anthers almost separate. Fertile involucre (fruit) ellipsoid, obovoid, or top-shaped, closed, pointed, resembling an achene and inclosing a single flower; elongated style-branches protruding. Achenes ovoid. — Coarse homely weeds, with opposite or alternate lobed or dissected leaves, and inconspicuous greenish flowers, in late summer and autumn; ours annuals, except the last. (The Greek and later Latin name of several plants, as well as of the food of the gods.)

Sterile heads in single or panicled racemes or spites, the involucre regular.

Leaves opposite, only once lobed; sterile involucre 3-ribbed on one side.

A. trífida L. (GREAT R.) Stem stout, 1-6 m. high, rough-hairy, as are the large deeply 3-lobed leaves, the lobes oval-lanceolate and serrate; petioles margined; fruit obovoid, 5-6-ribbed and tubercled. — Rich soil, common westw. and southw., much less so northeastw. Var. integrifòlia (Muhl.) T. & G. Smaller, with the upper leaves (or all of them) undivided, ovate or oval.—Same habitat, not rare.

Very similar to its cousin the Black-Eyed Susan (R. hirta), but note the branching habit and the smaller flower heads with shorter, rounder rays. These plants grew in a sunny meadow in Sewickley Heights, where they were blooming in late August.

Flowers. Heads with large, conical or hemispherical brown disk; about 8 short, elliptical golden rays.

Leaves. Rough; upper sessile, with shallow teeth, ovate, pointed; lower often with 3 irregular lobes.

Stem. Rough-hairy, purple; frequently branching; about 3 feet (1 m) high.

Gray describes the genus and the species:

RUDBÉCKIA L. CONE-FLOWER. Heads many-flowered, radiate; the rays neutral. Bracts of the involucre leaf-like, in about 2 rows, spreading. Receptacle conical or column ir ; the short chaff concave, not rigid. Achenes 4-angled (in our species), smooth, not margined, flat at the top, with no pappus, or a minute crown-like border. — Chiefly perennial herbs, with alternate leaves, and showy terminal heads; the rays generally long, yellow, often darker at base. (Named in honor of the Professors Rudbeck, father and son, predecessors of Linnaeus at Upsal.)

Achenes annular; chaff persisting in age.

Disk hemispherical to ellipsoid-ovoid in fruit, dark purple or brown.

Lower leaves 3-lobed or parted.

R. triloba L. Hairy, biennial, much branched, 0.5-1.6 m. high; branches slender and spreading; upper leaves ovate-lanceolate, sparingly toothed; lower 3-lobed, tapering at base, ooarsely serrate (those from the base pinnately parted or undivided); rays 8-10, oval or oblong; chaff of the black-purple depressed-globular disk smooth, awned. — Rich soil, N. J. to Minn., Kan., and southw.; escaped from cultivation further northeastw. July, Aug. — Heads small, but numerous and showy.

These giant cousins of the Black-Eyed Susan (R. hirta) can grow twice the height of a man if they put their minds to it. They are magnificent and unmistakable in at least two important ways:

1. The flower heads, with green disk florets and pale yellow somewhat reflexed rays.

2. The lower leaves, which are large, deeply divided, and attached to the stem on broad winged petioles.

The flowers above were growing along a gravel road through the woods near Cranberry; the ones to the right were growing in the woods at the edge of a cemetery near Export. Both were blooming in late August.

Note that Gray’s description below puts the height at 2 m at most, but other sources mention that this species can grow up to 12 ft. (about 4 m), and the plants in the photograph at right were at least 9 ft. (3 m) tall.

RUDBECKIA L. CONE-FLOWER. Heads many-flowered, radiate ; the rays neutral. Bracts of the involucre leaf-like, in about 2 rows, spreading. Receptacle conical or column ir ; the short chaff concave, not rigid. Achenes 4-angled (in our species), smooth, not margined, flat at the top, with no pappus, or a minute crown-like border. — Chiefly perennial herbs, with alternate leaves, and showy terminal heads; the rays generally long, yellow, often darker at base. (Named in honor of the Professors Rudbeck, father and son, predecessors of Linnaeus at Upsal.)

Achenes annular; chaff persisting in age.

Disk columnar in fruit, dull greenish-yellow.

Leaves divided or cut.

R. laciniàta L. Stem smooth, branching, 0.5-2 m. high; leaves smooth or roughish, the lowest pinnate, witli 5-7-cut or 3-lobed leaflets ; upper leaves irregularly 3-5-parted, their lohes ovate-lanceolate, pointed, or the uppermost undivided ; heads long-pedunclod ; disk at first globular or hemispherical ; chaff truncate, downy at tip ; rays oblanceolate, 3-5 cm. long, drooping. — Low thickets, w. Me. and w. Que., westw. and southw. July-Sept.