Flora Pittsburghensis

Author: Father Pitt

  • Japanese Hops (Humulus japonicus)

    In many ways an attractive vine, but a very invasive one, and all the harder to get rid of because it is covered with sticky prickles. It can cover a huge area quickly, and seems to be found more and more commonly in the Pittsburgh area. Easily mistaken at first glance for a wild cucumber, but distinguishable by the greenish (rather than pure white) male flowers and the deeply five-to-seven-lobed (rather than more shallowly five-lobed) leaves.

    Male flowers and female flowers are borne on separate plants; the female flower clusters are similar to the ones on the familiar domestic hops (H. lupulus) used in making beer. (Japanese hops are said to be poor for beer-making.) The male flowers, which stand up above the vines, are the ones you will notice in a large patch.

    These vines were growing in Bird Park in Mount Lebanon, where they were blooming in the middle of September.

    This plant had not yet commonly escaped when most of the standard references were written, but Britton’s Manual of the Flora of the Northern States and Canada includes it in an appendix:

    HUMULUS L. (See Appendix.) Herbaceous perennial rough vines, with broad opposite thin petioled palmately veined leaves, lanceolate membranous stipules, and dioecious axillary flowers, the staminate panicled, the pistillate in ament-like drooping clustered spikes. Staminate flowers with a 5-parted calyx, the segments distinct and imbricated, and 5 short erect stamens. Pistillate flowers in 2’s in the axil of each bract of the ament. consisting of a membranous entire perianth, clasping the ovary, and 2 filiform caducous stigmas. Fruiting aments cone-like, the persistent bracts subtending the compressed ovate achenes. Endosperm fleshy. Embryo spirally coiled. [Name said to be the diminutive of the Latin humus, earth.] Two species, the following [H. lupulus] widely distributed through the north temperate zone, the other [H. japonicus, our current subject] native of northeastern Asia.

    Humulus Japonicus Sieb. & Zucc. Japanese Hop. A twining vine, similar to the Common Hop, the leaves deeply pedately 5-7-cleft. Pistillate aments few-flowered, their bracts and bractlets deltoid, acuminate, hispid-pubescent at least on the margins, not glandular. In waste ground, Conn, to D.C. Introduced from Japan. Aug.-Sept.

  • Spotted Knapweed (Centaurea maculosa)

    These beautiful flowers, close relatives of the garden Bachelor’s Button (Centaurea cyanus), seem to be found almost exclusively along railroads. We have three pictures now of this species, each beside a different railroad; this particular plant was part of a colony growing by the railroad viaduct that separates the South Side Flats from the Slopes, where it was blooming at the end of July. (The other two pictures are here and here.)  The color is variable from purple through white, but this purplish pink is by far the most common color.

    Gray describes the genus and the species:

    CENTAUREA L. STAR THISTLE. Heads many-flowered; flowers all tubular, the marginal often much larger (as it were radiate) and sterile. Receptacle bristly. Involucre ovoid or globose, imbricated; the bracts margined or appendaged. Achenes obovoid or oblong, compressed or 4-angled, attached obliquely at or near the base; pappus setose or partly chaffy, or none. Herbs with alternate leaves; the single heads rarely yellow. (Kentaurie, an ancient Greek plant-name, poetically associated with Chiron, the Centaur, but without wholly satisfactory explanation.)

    C. maculosa Lam. Pubescent or glabrate, with ascending rather wiry branches; involucre ovoid-cainpanulate, in fruit becoming open-campanulate; the outer and middle ovate bracts with rather firm points and with 5-7 pairs of cilia at the dark tip; innermost bracts elongate, entire or lacerate; corollas whitish, rose-pink, or purplish, the marginal falsely radiate. Waste places, roadsides, etc., N. E. to N. J. (Adv. from Eu.)

  • Purple Giant Hyssop (Agastache scrophulariifolia)

    Spelled A. scrophilariaefolia in Gray. Not a terribly common plant around here; this patch was growing in a clearing in Scott, where it was blooming in late August. The flowers are irresistibly attractive to butterflies. The leaves have a noticeable anise scent, not as strong as but very much like the scent of its more commonly cultivated cousin, Anise Hyssop (A. foeniculum). The two species are very similar; the most obvious difference is in the length of the flower spikes, which in A foeniculum are usually not much longer than your thumb, but in this species can easily exceed your longest finger.

    Gray describes the genus and the species:

    AGÁSTACHE Clayt. GIANT HYSSOP. Calyx tubular-bell-shaped, 15-nerved, oblique, 5-toothed, the upper teeth rather longer than the others. Upper lip of corolla nearly erect, 2-lobed, the lower 3-cleft, with the middle lobe crenate. Stamens 4, exserted; the upper pair declined, the lower and shorter pair ascending, so that the pairs cross; anther-cells nearly parallel. —Perennial tall herbs, with petioled serrate leaves, and small flowers crowded in interrupted terminal spikes in summer. (From agan, much, and stachys, an ear of corn, in reference to the numerous spikes.) Lophanthus Benth., in part.

    A. scrophulariaefòlia (Willd.) Ktze. Stem (obtusely 4-angled) and lower surface of the ovate or somewhat heart-shaped acute leaves slightly pubescent: spikes 0.6-5 dm. long; calyx-teeth lanceolate, acute, shorter than the purplish corolla; otherwise like the preceding [A. nepetoides]. (Lophanthus Benth.)—N. H. to Out., Mo., Ky., and Va. Var. Mollis (Fernald) Heller. Stems and lower surfaces of leaves densely villous. — Vt. and Ct. to Ill.

    [Because Gray’s description of this species refers to his description of A. nepetoides, here is that description: 

    A. nepetoides (L.) Ktze. Stem stout, 0.7-1.5 m. high, sharply 4-angled, smooth or nearly so; leaves ovate, somewhat pointed, coarsely crenate-toothed, 6-12 cm. long; spikes 3-12 cm. long, crowded with the ovate pointed bracts; calyx-teeth ovate, rather obtuse, little shorter than the pale greenish-yellow corolla. (Lophanthus Benth.) — Borders of woods, e. Mass., Vt., and w. Que. to Minn., and southw.]

    The famous naturalist William Bartram found this species in New Jersey near Philadelphia, and reported it as Hyssopus scrophularifolius in his Copendium Florae Philadelphicae:

    H. spikes verticillatc, cylindric; styles longer than the corolla; leaves cordate-ovate, acuminate, obtusely dentate.—Wilhl. and Pursh.

    Agastache, Gronovius, Fl. Virg. 88.
    Icon. Herm. parad. t. 106.

    A very rare plant, easily known from the preceding [Agastache nepetoides]. From fourteen inches to two feet high. Flowers purple. On the banks of the Delaware, Jersey side, on the walk from Kaighn’s point to the next ferry below, close to a shady thicket. Perennial. July.

  • Spotted Joe-Pye-Weed (Eupatorium maculatum)

    UPDATE: An earlier version of this article gave the wrong species name in the title.

    Shorter than the more common Hollow Joe-Pye-Weed (E. fistulosum), with flatter cymes, and with leaves commonly in whorls of 4 rather than 6. The two species sometimes grow side by side, as they did here in a damp depression in Schenley Park, where they were both blooming in early August.

    Most botanists today place the Joe-Pye-Weeds in the genus Eutrochium, making this Eutrochium maculatum; we keep the more familiar name for the convenience of Internet searchers.

    Once again, we turn to Alphonso Wood for a description:

    EUPATORIUM.

    Dedicated to Eupator, king of Pontus, who first used the plant m medicine.

    Flowers all tubular; involucre imbricate, oblong; style much exserted, deeply cleft; anthers included; receptacle naked, flat ; pappus simple, scabrous; achenia 5-angled.—Perennial herbs, with opposite or verticillate leaves. Heads corymbose. Flowers of the cyanic series, that is, white, blue, red, &c., never yellow.

    * Leaves verticillate. Flowers purple.

    E. Maculatum. (E. purpureum, ß. Darl.) Spotted Eupatorium.

    Stem solid, striate, hispid or pubescent, greenish and purple, with numeróos glands and purple lines; the glands on the stem and leaves give out an acrid effluvium in flowering-time: leaves. triple-veined, 3-5 in a whorl.—Low grounds, U. S. and Can. Stem 4-6 ft. high. Leaves petiolate, 6-7 in. by 3-4 in., strongly serrate. Flowers purple. July-Sept.

  • Hollow Joe-Pye-Weed (Eupatorium fistulosum)

    Probably the most common species of Joe-Pye-Weed in our area. Most botanists today put Joe-Pye-Weeds in the genus Eutrochium; we keep the name Eupatorium for the convenience of Internet searchers.

    This magnificent plant, with its domes of dusty-rose flowers on towering stems, is common in damp fields and roadsides everywhere; these plants grew in a moist depression in Schenley Park, side by side with their close cousins the Spotted Joe-Pye-Weeds (E. maculatum). Enlightened gardeners who have space for a few eight-foot towers in their perennial beds are beginning to discover and make use of this plant, which can now be seen in some of Pittsburgh’s most tasteful gardens.

    The taxonomy of the Joe-Pye-Weeds seems to be in an awful mess. Alphonso Wood’s Class-Book of Botany seems to be closest to the modern botanists’ classification of this species, so we use Wood’s description here:

    EUPATORIUM.

    Dedicated to Eupator, king of Pontus, who first used the plant m medicine.

    Flowers all tubular; involucre imbricate, oblong; style much exserted, deeply cleft; anthers included; receptacle naked, flat ; pappus simple, scabrous; achenia 5-angled.—Perennial herbs, with opposite or verticillate leaves. Heads corymbose. Flowers of the cyanic series, that is, white, blue, red, &c., never yellow.

    * Leaves verticillate. Flowers purple.

    E. fistulosum Barratt. (E. purpureum Willd. in part. E. incarnatum Linn., in part. E. purpureum, v. angustifolium T. & G.) Trumpet-weed.—Stem fistulous, glabrous, glaucous-purple, striate or fluted; leaves in about 12 whorls of 6s, largest in the middle of the stem, rather finely glandular-serrate; midvein and veinlets livid purple; corymb globose, with whorled peduncles.—Thickets, U. S. and Can., very abundant in the Western States! Height 6-10 ft., hollow its whole length. Leaves, including the 1″ petiole, 8″ by 2″. Corymb often 1 ft. diam. Flowers purple. The glaucous hue and suffused redness of this majestic plant are most conspicuous in flowering-time. It does not appear to possess the acrid properties of E. maculatum. July—Sept.