Category: Asteraceae

  • Late Thoroughwort (Eupatorium serotinum)

    Eupatorium-serotinum-2009-10-24-Oakmont

    Some of the Late Thoroughworts are stlil blooming as October fades into November. They can hybridize with other members of the genus Eupatorium, but this one appears to be a pure strain—note the smooth leaves, with petioles and without teeth, which set this species apart from either Boneset (Eupatorium perfoliatum) or White Snakeroot (Eupatorium rugosum). It was blooming in late October along a seldom-used railroad siding in Oakmont.

    From Gray’s Manual of Botany: Eupatorium serotinum Michx. Stem pulverulent-pubescent, bushy-branched, 1-2 m. high; leaves ovate-lanceolate, tapering to a point, triple-nerved and veiny, coarsely serrate, 0.5-1.5 dm. long; involucre very pubescent. Alluvial ground, Md. to Minn., e. Kan., and south w.

  • Canada Thistle (Cirsium arvense)

    Cirsium-arvense-2009-10-24-Oakmont

    This would certainly be one of our most prized ornamentals if it weren’t prickly, ubiquitous, and ineradicable. The seeds are prized by goldfinches, which are among our most ornamental birds. This plant was blooming in late October along a seldom-used railroad siding in Oakmont.

    Gray describes the genus and the species:

    CIRSIUM [Tourn.] Hill. COMMON or PLUMED THISTLE

    Heads many-flowered; flowers all tubular, perfect and similar, rarely imperfectly dioecious. Bracts of the ovoid or spherical involucre imbricated in many rows, tipped with a point or prickle. Receptacle thickly clothed with soft bristles or hairs. Achenes oblong, flattish, not ribbed; pappus of numerous bristles united into a ring at the base, plumose to the middle, deciduous. Herbs, mostly biennial; the sessile alternate leaves often pinnatifid, prickly. Heads usually large, terminal. Flowers reddish-purple, rarely white or yellowish; in summer. (Name from kirsos, a swelled vein, for which the Thistle was a reputed remedy.) CNICUS of many auth., not L. By some recent Am. auth. included in CARDUUS.

    * * * * Outer bracts of the appressed involucre barely prickly-pointed; heads mostly small and numerous. None of the leaves strongly decurrent.

    13. C. ARVENSE (L.) Scop. (CANADA THISTLE.) Perennial, slender, 3-9 dm. high, the rootstock extensively creeping; leaves oblong or lanceolate, smooth, or slightly woolly beneath, finally green both sides, strongly sinuate-pinnatifid, very prickly-margined, the upper sessile hut smrrcly decurrent; heads imperfectly dioecious; flowers rose-purple or whitish. (Carduus Robson; Cnicus Hoffm.) Cultivated fields, pastures, and roadsides, common; a most troublesome weed, extremely difficult to eradicate. (Nat. from Eu.) Var. VEST!TUM Wimm. & Grab. Leaves permanently white-lanate beneath. Locally established. (Nat. from Eu.) Var. INTEGRIFOLIUM Wimm. & Grab. Leaves  chiefly plane and uncut, or the lowest slightly pinnatifid. Local, Que., N. E., and N. Y. (Nat. from Eu. )

  • Canada Goldenrod (Solidago canadensis)

    Solidago-canadensis-2009-09-25-Oakmont-02

    Goldenrods are the bees’ best friends. This one, which was blooming in late September, grew in front of a corrugated steel fence near a disused railroad siding in Oakmont. It may be common to the point of superabundance, but there is no more elegant wild flower than Canada Goldenrod.

    From Gray’s Manual of Botany: S. canadensis L. Stem rather slender, 0.3-1.5 m. high, glabrous at least below, often minutely pubescent above; leaves narrowly lanceolate, thin, glabrous above, minutely pubescent on the nerves beneath, mostly sharp-serrate, the middle ones 6-13 cm. long, 5-18 mm. wide; heads tiny, crowded in recurved racemes and forming dense broadly pyramidal panicles; pedicels strongly pilose; involucral bracts linear, mostly attenuate, greenish-straw-color. (Var. glabrata Porter.) Thickets and rich open soil, Nfd. to N. Dak., s. to W. Va. and Ky. July-Sept.

  • Fleabane (Erigeron strigosus)

    Erigeron-strigosus-2009-08-26-Export-01

    Also called “Daisy Fleabane,” “Fleabane Daisy,” “Plains Fleabane,” “Prairie Fleabane,” and probably many other names. Pittsburghers usually call them “little daisies.” Old herbal legend has it that dried plants repel fleas. Fleabane is very common around here; if it were not, it would be treasured as a garden ornamental. It blooms for a good bit of the summer; these were blooming in late August at the edge of a back yard near Export. The seventh edition of Gray lists this as Erigeron ramosus, though the sixth had listed it as E. strigosus.

    Gray describes the genus and the species:

    ERIGERON L. FLEABANE
    Heads many-flowered, radiate, mostly flat or hemispherical; the narrow rays very numerous, pistillate. Involucral bracts narrow, equal, and little imbricated, never coriaceous, neither foliaceous nor green-tipped. Receptacle flat or convex, naked. Achenes flattened, usually pubescent and 2-nerved; pappus a single row of capillary bristles, with minuter ones intermixed, or with a distinct short outer pappus of little bristles or chaffy scales. Herbs, with entire or toothed and generally sessile leaves, and solitary or corymbed naked-pedunculate heads. Disk yellow; rays white, pink, or purple. (The ancient name presumably of a Senecio, from er, spring, and geron, an old man, suggested by the hoariness of some vernal species.)

    E. ramosus (Walt.) BSP. (DAISY F.) Stem panicled-corymbose at the summit, roughish like the leaves with minute appressed hairs, or almost smooth; leaves entire or nearly so, the upper lanceolate, scattered, the lowest oblong or spatulate, tapering into a slender petiole; rays white, twice the length of the minutely hairy involucre. (E. strigosus Muhl.) Fields, etc., common. June-Oct. Stem smaller and more simple than the preceding [E. annuus], with smaller heads but longer rays. Var. DISCOIDEUS (Robbins) BSP., with the rays minute, scarcely exceeding the involucre, occurs in s. N. E. and N. Y.

  • Late Goldenrod (Solidago gigantea)

    Solidago-gigantea-2009-10-12-Beechview-03

    Rivals Canada Goldenrod for sheer yellow spectacle, but comes out in October and into November, after the Canada Goldenrods have mostly gone to seed. Note the long rays on the individual heads, giving the whole tuft of yellow a distinctive shaggy look. These plants were blooming in mid-October under a streetcar overpass in Beechview. Gray lists this as Solidago serotina var. gigantea.

    From Gray’s Manual: S. serotina Ait. Stem stout, 0.6-2.5 m. high, smooth, often glaucous; leaves quite smooth both sides, lanceolate to oblanceolate, taper-pointed, very sharply serrate, except the narrowed base, rough-ciliate; the middle ones 7-16 cm. long, 1-3 cm. wide; the ample panicle pubescent; involucre 3.5-5 mm. long, its bracts linear, subherbaceous; rays 7-14, rather long. Thickets, in rich soil, N. B. to B. C., and southw. July-Sept.

    Var. gigantea (Ait.) Gray. Leaves glabrous above, slightly pubescent beneath, especially on the nerves; involucre 3.2-4 mm. long. Low ground, e. Que. to Ill., and southw.