The white form of the Zigzag Aster (for which the preferred botanical name is now Symphyotrichum prenanthoides) is not terribly rare, though far less common than the blue form. Here we see the white form in the foreground, and the blue in the background. All shades between pale blue and white occur, so it’s very hard to mark where blue ends and white begins.

This plant was growing along a trail in Bethel Park, where it was blooming in early October.

We repeat the description we gave when we presented the blue form:

Flowers. Heads about an inch and a quarter wide, in irregular corymbs; disk flowers yellow, fading to red-brown; rays pale blue or violet, sometimes white, linear, numerous.

Leaves. Variable: alternate; lanceolate or ovate-lanceolate, with sharp and narrow points; strong central rib; rough, outward-facing hairs noticeable when rubbed toward stem; lower leaves on petioles with broad wings clasping the stem; upper sessile and clasping. On some plants the leaves are jaggedly toothed; on others the teeth are less prominent, with the upper leaves almost entire.

Stem. Tough, wiry; with purplish vertical lines; arching, about 1 or 2 feet high; characteristically zigzag from leaf to leaf, as in the picture at right.

Gray describes the genus Aster and the species:

ÁSTER [Tourn.] L. STARWORT. FROST-FLOWER. ASTER. Heads many-flowered, radiate; the ray-flowers in a single series, fertile. Bracts of the involucre mure or less imbricated, usually with herbaceous or leaflike tips. Receptacle flat, alveolate. Achenes more or less flattened; pappus simple, of capillary bristles (double in §§ 4 and 5). — Perennial herbs (annual only in §§ 7 and 8), with corymbed, panicled, or racemose heads, flowering chiefly in autumn. Rays white, purple, blue, or pink; the disk yellow, often changing to purple. Species often without sharply defined limits, freely hybridizing. (Name aster, a star, from the radiate heads of flowers. )

A. prenanthoìdes Muhl. Stem 1 m. or less high, corymbose-panicled, hairy above in lines; leaves rough above, smooth underneath, ovate to lanceolate, sharply cut-toothed in the middle, conspicuously taper-pointed, and rathrr abruptly narrowed to a long contracted entire portion, which is abruptly dilated into a conspicuously auricled base; heads on short divergent peduncles; involucre 5-8 mm. high; bracts narrowly linear, tips recurved-spreading; rays violet. — Borders of streams and rich woods, w. N. E. to Va. and Ky., w. to Minn, and la. Aug.-Oct.

Now Symphyotrichum prenanthoides. This is probably our most common roadside blue aster. The Zigzag Aster is so named from its crooked stem (which also gives it the name “Crooked-Stemmed Aster”).This plat was growing along a trail in Bethel Park, where it was blooming in early October.

Asters laugh at the notion of “species,” as Gray notes in his description of the genus, so it’s always best to regard any identification, even a fairly sure one like this, as tentative.

Flowers. Heads about an inch and a quarter wide, in irregular corymbs; disk flowers yellow, fading to red-brown; rays pale blue or violet, sometimes white, linear, numerous.

Leaves. Variable: alternate; lanceolate or ovate-lanceolate, with sharp and narrow points; strong central rib; rough, outward-facing hairs noticeable when rubbed toward stem; lower leaves on petioles with broad wings clasping the stem; upper sessile and clasping. On some plants the leaves are jaggedly toothed; on others the teeth are less prominent, with the upper leaves almost entire.

Stem. Tough, wiry; with purplish vertical lines; arching, about 1 or 2 feet high; characteristically zigzag from leaf to leaf, as in the picture at right.

Gray describes the genus Aster and the species:

ÁSTER [Tourn.] L. STARWORT. FROST-FLOWER. ASTER. Heads many-flowered, radiate; the ray-flowers in a single series, fertile. Bracts of the involucre mure or less imbricated, usually with herbaceous or leaflike tips. Receptacle flat, alveolate. Achenes more or less flattened; pappus simple, of capillary bristles (double in §§ 4 and 5). — Perennial herbs (annual only in §§ 7 and 8), with corymbed, panicled, or racemose heads, flowering chiefly in autumn. Rays white, purple, blue, or pink; the disk yellow, often changing to purple. Species often without sharply defined limits, freely hybridizing. (Name aster, a star, from the radiate heads of flowers. )

A. prenanthoìdes Muhl. Stem 1 m. or less high, corymbose-panicled, hairy above in lines; leaves rough above, smooth underneath, ovate to lanceolate, sharply cut-toothed in the middle, conspicuously taper-pointed, and rathrr abruptly narrowed to a long contracted entire portion, which is abruptly dilated into a conspicuously auricled base; heads on short divergent peduncles; involucre 5-8 mm. high; bracts narrowly linear, tips recurved-spreading; rays violet. — Borders of streams and rich woods, w. N. E. to Va. and Ky., w. to Minn, and la. Aug.-Oct.

A thoroughwort worthy of the name: the stems go right through the paired leaves. The name “Boneset” refers to its supposed assistance in setting broken bones.According to the ancient Doctrine of Signatures, the all-wise Creator has embedded a secret sign in each useful herb to show us what it can be used for: in this case, the joined leaves are supposed to show us that the herb can join what has been broken. Modern scientists have concluded that the all-wise Creator wasn’t as dumb as all that and must have given us a surer way to find useful medicines, which is why we have the scientific method.

Boneset likes a wet location; this plant was growing in a roadside ditch near Cranberry, where it was blooming in late August.

Gray describes the genus and the species:

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. EUPATORIUM proper. Receptacle flat.

Heads 8-20-flowered; involucre of 8-15 more or less imbricated and unequal bracts, the outer ones shorter; flowers white or nearly so.

Leaves sessile or nearly so, with a broad base, opposite or in threes; heads pubescent.

Leaves opposite, clasping or united at the base, long, widely spreading; heads 10-40-flowered; corymbs very compound and large.

E. perfoliàtum L. (THOROUGHWORT, BONESET.) Stem stout, 0.5-1.6 m. high, hairy; leaves lanceolate, united at the base around the stem (connateperfoliate), tapering to a slender point, serrate, very veiny, wrinkled, downy beneath, 1-2 dm. long; bracts of the involucre linear-lanceolate. — Low grounds; common and well known.

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).