Flora Pittsburghensis

Category: Asteraceae

  • Philadelphia Fleabane

    The amazing number of ray flowers gives these flower heads either a delicate or a shaggy appearance, depending on how much they’ve been whipped about by the wind. The rays can be either white or, as here, pink. The flowers start to bloom in May; these were blooming in Squirrel Hill on about May 15.

    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. philadelphicus L. Hairy; stem leafy, corymbed, bearing several small heads; leaves thin, with a broad midrib, oblong; the upper smoothish, clasping by a heart-shaped base, mostly entire ; the lowest spatulate, toothed; rays innumerable and very narrow, rose-purple or flesh-color. Throughout, locally common, generally in alluvial soil. May-Aug.

  • New York Ironweed (Vernonia noveboracensis)

    Few floral sights are more spectacular than a meadow filled with Ironweed, whose vivid purple can never be adequately captured in a photograph. This meadow was blooming in early September along a tributary of the Pine Creek near Wexford.

    Gray describes the genus and the species:

    VERNONIA Schreb. IRONWEED
    Heads discoid, 16-many-flowered, in corymbose cymes; flowers perfect; involucre shorter than the flowers, of much imbricated bracts. Achenes cylindrical, ribbed; pappus double, the outer of minute scale-like bristles, the inner of copious capillary bristles. Perennial herbs, with leafy steins, alternate acuminate or very acute serrate leaves and mostly purple (rarely white) flowers. (Named for William Vernon, an early English botanist, who traveled in North America. )

    V. noveboracensis Willd. Rather tall (1-2 m.); leaves long-lanceolate to lance-oblong, more or less pubescent beneath, gradually narrowed but not at all acuminate toward the base; cyme open; heads mostly 30-40-flowered; involucre purplish (or in white-flowered individuals green), campanulate; the bracts ovate or lance-ovate, with loosely ascending or recurved-spreading filiform tips; pappus purple or purplish. Low ground near the coast, Mass, to Va. and Miss.; reported from Pelee I., L. Erie (Macoun).

  • Sow Thistle (Sonchus oleraceus)

    Nasty prickly weeds that they are, the Sow Thistles have a certain architectural elegance. The buds are shaped like a fine glass vase, and the clasping leaves are a particulary attractive dark green. Sow Thistles are edible, apparently, if you catch them young or don’t mind sticking sharp things in your mouth. This one was blooming beside a telephone pole in Beechview in early November.

    Gray describes the genus and the species:

    SONCHUS [Tourn.] L. SOW THISTLE.
    Heads many-flowered, becoming tumid at base. Involucre more or less imbricated. Achenes obcompressed, ribbed or striate, not beake; pappus copious, of very white exceedingly soft and fine bristles mainly falling together. Leafy -stemmed coarse weeds, chiefly smooth and glaucous, with corymbed or umbellate heads of yellow flowers produced in summer and autumn. (The ancient Greek name.)

    Annual; flowers pale yellow.

    S. OLERACEUS L. (COMMON S.) Stem-leaves runcinate-pinnatifid, rarely undivided, slightly toothed with soft spiny teeth, clasping by a heart-shaped base, the auricles acute; involucre downy when young; achenes striate, also wrinkled transversely. Waste places, chiefly in manured soil and around dwellings. (Nat. from Eu.)

  • Woodland Sunflower (Helianthus divaricatus)

    Normally a late-summer flower, but this one was gamely blooming in early November after more than one frost, when perennial sunflowers are supposed to be settling in for the winter. It likes shade, and is happiest at the edge of a woodland clearing; this one was growing along a thickly wooded street in Beechview. Note the opposite lanceolate leaves with shallow teeth and the slightly sloppy downward-facing pointed bracts.

    Gray describes the genus and the species:

    HELIANTHUS 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 chaffy scales on the principal angles, and sometimes 2 or more small intermediate scales. —Coarse and stout herbs, with solitary or corymbed heads, and yellow rays; flowering toward autumn. (Named from helios, the sun, and anthos, a flower.)

    H. divaricatus L. Stem simple or forked and corymbed at the top, 0.5-2 m. high, smooth below; leaves all opposite and divaricate, ovate-lanceolate, 3-nerved from the rounded or truncate sessile base, tapering gradually to a sharp point, 0.5-2 dm. long, serrate, thickish, rough both sides; bracts narrowly lanceolate, attenuate, ciliate, equaling the disk (1 cm. wide); rays 8-12, 2.5 cm. long. Thickets and barrens, s. Me. to L. Winnipeg, Neb., and southw.

  • Zigzag Aster (Aster prenanthoides)

    Now Symphyotrichum prenanthoides. Blue asters are among the last flowers of the fall. Identifying asters is, of course, a foolish endeavor, but this one has the clasping leaves and zigzag stem that identify a Zigzag Aster. It was blooming at the edge of the woods near the parking lot of the Pittsburgh Zoo in late October.

    From Gray’s Manual:

    A. prenanthoides 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 rather 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. Minn, and Ia. Aug.-Oct.