Flora Pittsburghensis

Author: Father Pitt

  • Giant Ragweed (Ambrosia trifida)

    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.

  • Orange Touch-Me-Not (Impatiens capensis)

    Also called Spotted Touch-Me-Not or Jewelweed. Very similar to the Yellow or Pale Touch-Me Not (I. pallida), and often found in the same colony. Most of the differences are subtle; I. capensis tends to have smaller, darker leaves, often with a noticeable bluish tinge. The flowers, however, leave no doubt about the species: the bright orange of I. capensis is instantly obvious. Since the flowers bloom from late June to the first frost, we can rely on them to identify the plant. These were blooming at the edge of a field near Cranberry in late August.

    The specific name capensis is unfortunate. The botanist who named it thought the specimen came from the Cape Colony in Africa. The names Impatiens fulva and I. biflora were current for much of the nineteenth and twentieth centuries; but the inflexible rule of priority has asserted the rights of the name capensis, however wrongheaded it may be.

    Gray describes the genus and the species:

    IMPATIENS [Rivinius] L. BALSAM, JEWELWEED. Sepals apparently only 4; the anterior one notched at the apex (probably two combined); the posterior one (appearing anterior as the flower hangs on its stalk) largest, and forming a usually spurred sac. Petals 2, 2-lobed (each a pair united). Filaments appendaged with a scale on the inner side, the б scales connivent over the stigma; anthers introrse. Pod with evanescent partitions, and a thick axis bearing several anatropous seeds; valves 6, coiling elastically and projecting the seeds in dehiscence. — Leaves in ours ovate or oval, coarsely toothed, petioled. Flowers axillary or panicled, often of two sorts, viz., the larger ones which seldom ripen seeds; and very small ones which are fertilized early in the bud, their floral envelopes never expanding but forced off by the growing pod and carried upward on its apex. (Name from the sudden bursting of the pods when touched, whence also the popular appellation.)

    I. biflora Walt. (SPOTTED TOUCH-ME-NOT.) Flowers orange-color, thickly spotted with reddish brown; sac longer than broad, acutely conical, tapering into a strongly inflexed spur half as long as the sac. (I. fulva Nutt) — Rills and shady moist places. June-Sept. —Plant 6-8 dm. nigh. Forms with spotless, whitish, or roseate flowers have been found.

  • Yellow Touch-Me-Not (Impatiens pallida)

    Also called Pale Touch-Me-Not or Jewelweed. The name “Touch-Me-Not” comes from the explosive seedpods, which give no end of entertainment to children and any adults who are not beyond being entertained by natural amusements. The pods have parallel ribs connected by a thin membrane, and the membrane gets thinner and weaker as the pod ripens. At length the membrane can be ruptured by the slightest touch, and then the ribs instantly coil into springs, sending seeds flying in all directions.

    These plants are close relatives of the garden Impatiens, which have similarly explosive seedpods. All Impatiens species have thick, juicy stems, and large colonies of them will form dense, even mounds.

    We have two species of Touch-Me-Not in the area. Yellow Touch-Me-Not is more common in the north and at higher elevations; Orange or Spotted Touch-Me-Not (I. capensis) is more common in the south and at lower elevations. Pittsburgh is right where the ranges meet, so we get both, often in the same colony. The yellow species is more common here, but the orange is also very common, especially in lower areas.

    The juice from the thick stems is supposed to be a good preventative for poison ivy if rubbed on the affected parts soon after exposure.

    Gray describes the genus and the species:

    IMPATIENS [Rivinius] L. BALSAM, JEWELWEED. Sepals apparently only 4; the anterior one notched at the apex (probably two combined); the posterior one (appearing anterior as the flower hangs on its stalk) largest, and forming a usually spurred sac. Petals 2, 2-lobed (each a pair united). Filaments appendaged with a scale on the inner side, the б scales connivent over the stigma; anthers introrse. Pod with evanescent partitions, and a thick axis bearing several anatropous seeds; valves 6, coiling elastically and projecting the seeds in dehiscence. — Leaves in ours ovate or oval, coarsely toothed, petioled. Flowers axillary or panicled, often of two sorts, viz., the larger ones which seldom ripen seeds; and very small ones which are fertilized early in the bud, their floral envelopes never expanding but forced off by the growing pod and carried upward on its apex. (Name from the sudden bursting of the pods when touched, whence also the popular appellation.)

    I. pallida Nutt. (PALE TOUCH-ME-NOT.) F’lowers pale-yellow, sparingly dotted with brownish-red; sac dilated and very obtuse, broader than long, tipped with a short incurved spur. (I. aurea Muhl. ?) — Moist shady places and along rills, in rich soil, n. Me. and w. N. E., westw. and southw. July-Sept. — Larger and greener than the next [I. capensis], with larger flowers. A form with unspotted flowers occurs.

  • Morning Glory (Ipomoea purpurea)

    An introduced ornamental that has become quite weedy, especially in the city of Pittsburgh, where it covers banks and winds through vacant lots with gay abandon. These vines grew on a fence in Beechview, where they were blooming at the beginning of September.

    Flowers. Large and showy; trumpet-shaped, like an old phonograph horn; five-parted, with white center and contrasting darker markings radiating from the center. They come in several colors, from the deepest velvety purple to bright pink. They close by midday, or later if the weather is chilly or dark.

    Leaves. Heart-shaped, or on vigorous and high-growing vines sometimes three-lobed, like a grape leaf; smooth above, lightly rough-hairy below; strongly veined.

    Stem. Hairy; bright green; long and climbing; climbs by wrapping itself around any support, often bundling with other stems from the same plant, forming a dense mound; can climb to 9 feet (3 m) or so in one season.

    Gray describes the genus and the species, which he places in the Euipomoea or Ipomoea-proper section of the genus:

    IPOMOÈA L. MORNING GLORY. Calyx not bracteate at base, but the outer sepals commonly larger. Corolla salver-form or funnel-form to nearly campanulate; the limb entire or slightly lobed. Capsule globular, 4-6 (by abortion fewer)-seeded, 2-4-valved. (Nаmе, according to Linnaeus, from ips, a Bindweed, and homoios, like; but ips is a worm.)

    § 2. EUIPOMOÈA Gray. Corolla funnel-form or nearly campanulate, contorted in the bud; stamens and style not exserted

    Lobes of stigma and cells 3, sepals long and narrow, attenuate upward, mostly hirsute below; corolla purple, blue, or white. (MORNING GLORY.)

    I. purpurea (L.) Roth. (COMMON M.) Annual; stems retrorsely hairy; leaves heart-shaped, acuminate, entire; peduncles long, umbellately 3-5-flowered; calyx bristly-hairy below; corolla funnel-form, 4.5-7 cm. long, purple, varying to white. — Escaped in cultivated grounds. (Introd. from Trop. Am.)

  • Thin-Leaved Coneflower (Rudbeckia triloba)

    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.