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.

Every botanical writer feels compelled to mention that this species is neither an artichoke nor from Jerusalem. One wonders whether anyone in the modern age has ever made that mistake. This is quite obviously a sunflower, though one more noted for its edible tuber than for its seeds. The flowers are delightful, to butterflies as well as to humans. The plant is very similar to Thin-Leaved Sunflower (H. decapetalus), but note the more robust leaves, hairy stem, and shorter bracts.

Flowers. Heads terminal on branching stalks. Disk flowers golden; rays (about 13) golden, darkening to pale orange toward center. Bracts about as long as the disk.

Leaves. Very rough; mid-green above, paler below; upper nearly sessile, lower on short petioles with tapering wings; mostly opposite, but upper alternate; upper nearly entire, lower with shallow teeth.

Stem. Narrow but very strong; purple most of its length; very hairy; branching, especially toward ends.

Gray describes the genus and the species:

HELIÁNTHUS L. Sunflower. Heads many-flowered; rays several or many, neutral. Involucre Imbricated, herbaceous or foliaceous. Receptacle flat or convex; the persistent chaff embracing the 4-sided and laterally compressed smooth achenes, which are neither winged nor margined. Pappus very deciduous, of 2 thin chafly scales on the principal angles, and sometimes 2 or more small intermediate scales. — Coarse and stout herbs, with solitary or corymbcd heads, and yellow rays; flowering toward autumn. (Named from helios, the sun, and anthos, a flower.)

§2. Perennials; receptacle convex or at length low-conical; lower leaves usually opposite.

Involucre looser, the bracts more acuminate or elongated or foliaceous.

Leaves all or most of them opposite, 3-nerved.

Leaves longer-petiolate, thinnish or soft, coarsely serrate, commonly broad; bracts loose, hirsute-ciliate.

H. tuberosus L. (JERUSALEM ARTICHOKE.) Pubescent or hirsute, 1.5-3.5 m. high; leaves ovate or subcordate to oblong-lanceolate, acuminate, scabrous above, minutely pubescent or cinereous beneath; bracts lanceolate, attenuate, little exceeding the disk; rays 12-20.—N. Y. to Minn., westw. and southw.; often cultivated, and introduced eastw.

–

In his Wild Flowers of New York (1914), Chester Albert Reed gives us some of the lore of this beautiful sunflower:

This is an interesting native plant  often known as the Wild Sunflower. Indians and early colonists used its tuberous roots much as we use potatoes today. It was also carried abroad and cultivated extensively, particularly in Italy, where it was known as Girasole Articocco (Sunflower Artichoke), from which name it was corrupted into the Jerusalem Artichoke as we know it now. The stalk, which grows from six to twelve feet in height is very rough and the three-ribbed, toothed-edged leaves, the lower ones of which are set oppositely on the stalk, are also rough,—this roughness presumably being to discourage crawling insects from reaching the summit. The several flower heads are two or three inches across and consist of from a dozen to twenty rays about a greenish-yellow center. This species naturally grows in somewhat moist thickets but is often seen in or about old gardens where it continues to grow as a reminder of the days when it was cultivated for food.

The thin leaves are indeed a distinguishing feature of this plant; most sunflowers have coarse and strong leaves, but these are thin and rather weak. These plants were growing on a shady wooded hillside above a back street in Beechview.

Flower Heads. The disk is smallish and golden yellow. The matching golden rays are long and narrow; there were ten to twelve of them on each of the flower heads on this plant, but (as the specific name implies) ten is a good average for this species. Note the long, narrow bracts, visible on the bud to the left in the photograph above.

Leaves. Thin; rough on some plants, smooth on others; ovate, pointed; toothed; upper leaves nearly sessile; lower on winged petioles.

Stem. Smooth and tough, green with a few red spots; about 4 feet tall.

Gray describes the genus and the species:

HELIÁNTHUS L. Sunflower. Heads many-flowered; rays several or many, neutral. Involucre Imbricated, herbaceous or foliaceous. Receptacle flat or convex; the persistent chaff embracing the 4-sided and laterally compressed smooth achenes, which are neither winged nor margined. Pappus very deciduous, of 2 thin chafly scales on the principal angles, and sometimes 2 or more small intermediate scales. — Coarse and stout herbs, with solitary or corymbcd heads, and yellow rays; flowering toward autumn. (Named from helios, the sun, and anthos, a flower.)

§2. Perennials; receptacle convex or at length low-conical; lower leaves usually opposite.

Involucre looser, the bracts more acuminate or elongated or foliaceous.

Leaves all or most of them opposite, 3-nerved.

Leaves longer-petiolate, thinnish or sofl, coarsely serrate, commonly broad; bracts loose, hirsute-ciliate.

H. decapétalus L. Stem branching, 0.5-1.5 m. high, smooth below; leaves smooth or roughish, ovate, pointed, abruptly contracted into margined petioles; bracts lanceolate-linear, elongated, loosely spreading, sometimes foliaceous, the outer longer than the disk; rays about 10 (H. scrophulariifolius Britton?) — Copses and low banks of streams, centr. Me. and w. Que. to Minn., Mo., and southw.