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Sweet-William's (Dianthus barbatus) inflorescence, located at the apex of the stem, is a flat-topped or slightly domed cyme of 5-30 flowers. Individual flowers are about an inch across consisting of a tubular calyx about 3/8" long with five sharply triangular lobes; five broad, variously colored petals that have very narrow bases ("clawed") and a toothed or fringed outer edge; 10 stamens with purplish anthers (which often fall off the filament); and two styles. Fertilized flowers produce oval to cylindrical seed capsules about 1/2" long with four teeth around the open end. The flowers of Sweet-William are edible. Sweet-William prefers deep, organic-rich, well drained soils in full sun, preferably in a disturbed site. The sweet William plants growing in Jackson Park are undoubtedly escapees from a nearby garden (a rare event). The only other Dianthus spp. in Jackson Park is Deptford pink (Dianthus armeria), also a perennial exotic. The two species are similar in having fringed petals and a terminal inflorescence, but otherwise you would never confuse them; Deptford pink is a subtle beauty, sweet William shouts for joy.

Dianthus

Dianthus barbatus

sweet-William [Blooms: Jun-Jul]

Aunt Lucy (Ellisia nyctelea) flowers arise from the leaf axils. The flowers are small and tubular (1/4" wide x 1/2" long); the five petallike lobes are white with purple lines or specks; the five stamens are hidden within the corolla, alternating with the corollar lobes and the style is divided for about half ts length; the sepals are hairy and as large as the petals. The fruit is a 1/4" long hairy, white body that looks like two spheres squashed together, resting on the sepals; it usually contains 4 seeds. This species is very common in late spring in open but shaded areas on Wooded Island. How it acquired the moniker "Aunt Lucy" is obscure.

Ellisia

Ellisia nyctelea

Aunt Lucy [Blooms: Apr-Jun]

Tall boneset flowerheads are tiny (1/8" across) with no ray florets and typically only five disc florets. Disc florets are dull white with a tubular corolla and a long bifurcated style that extends well away from the floret; the base of the style is greenish and surrounded by five brown stamens with white tips. The apex of the corolla has five prominant, triangular lobes that give the florets a star-like appearance.

Eupatorium

Eupatorium altissimum

tall boneset [Blooms: Aug-Oct]

Common boneset's upper stem and branches bear clusters 2-8" across of white flowerheads. Each flowerhead is about 4-6 mm across consisting of ~15-20 dull white disk florets (ray florets are absent); florets have a tubular corolla with five triangular lobes at the apical end and a long, bifurcated style surrounded at its base with a brown column of five stamens with purplish anthers. Ironically, "common" boneset is less common than late boneset or tall boneset in Jackson Park.

Eupatorium

Eupatorium perfoliatum

common boneset [Blooms: Jul-Aug]

Late boneset's inflorescence is a flat-topped or shallowly-domed panicle with numerous flowerheads. Individual flowerheads are composed of 12-15 greyish-white disk floret (ray florets are absent) about 1/4" long with a tubular corolla with five small, triangular apical lobes and a long white bifurcated style extending well out from the floret surrounded by five black stamens. Leaf venation, lack of leaf hairs, and and smaller flowerheads (~5-8 florets) distinguish tall bonset (E.altissium) from late boneset (E. serotinum; 12-15 florets).

Eupatorium

Eupatorium serotinum

late boneset [Blooms: Aug-Oct]

Gallant-soldier (aka, small-flowered galinsoga) flowerheads are about 1/4" across; they have 4-8 (usually 5) ray florets with a single minute (about 2x2 mm) white petal notched to produce two or three lobes; the ray florets are distributed around the circumstance of the disc. There are 15-50 golden yellow, tubular disc florets with five short triangular lobes at their apex. Both ray and disc florets are fertile; the ray florets are pistillate while the disc florets are perfect (both pistils and stamens). The fruit (a cypsela) consists of a black, conical seed suspended beneath about five off-white, papery, fringed scales that act as a parachute. Gallant-soldier is very similar to galinsoga (Galinsoga quadriradiata); the latter has larger flowerheads and ray floret petals.

Galinsoga

Galinsoga parviflora

gallant-soldier [Blooms: Aug-Sep]

Galinsoga (aka, Peruvian daisy or shaggy soldier) flowerheads are small (1/4" across) with 4-8 (usually five) widely separated 2.5 mm long, white ray florets with three teeth at their tips. The 15-35 disc florets are yellow. Both ray and disc florets are fertile; the ray florets are pistillate while the disc florets are perfect (both pistils and stamens). The fruit (a cypsela) consists of a black, conical seed suspended beneath about five off-white, papery, fringed scales that act as a parachute. A poisonous plant (Tridax procumbens) with nearly identical flowers (but distinctly different leaves) is (luckily) restricted to FL and TX in the U.S. so not likely to show up in Jackson Park. The name Galinsoga ciliata, sometimes still used for Galinsoga quadriradiata, is invalid (ITIS); according to the USDA Plants database, C. ciliata has been superceded by either G. quadriradiata or G. urticifolia.

Galinsoga

Galinsoga quadriradiata

galinsoga [Blooms: Jun-Oct]

Cream gentian the leaves are olive-green, lance-shaped with a pronounced fold along the midvein, 3" long and 2" across, and clasp the stem. Although most leaves are opposite (in pairs), the leaves just below the flowers occur in a whorl of three. The flowers are mostly apical, some version of white or cream, tubular, with the petal's veins outlined in green, about 1-2" tall and 3/4" across, and oriented near-vertically. The five petals remain tightly appressed, with only a small opening where their apices meet; the five stamens and pistil with a bifurcated stigma are usually hidden from view. Bumblebees are the primary pollinators.

Gentiana

Gentiana alba

cream gentian [Blooms: Jul-Oct]

Carolina crane's-bill flowers are small (about 1/4-3/8" across), in small clusters on stubby pedicels. Each flower contains five dull-green, very hairy, lance-shaped sepals with long, scarlet-tipped awns on the tips, five white to pinkish-lavendar petals shorter than the sepals, ten stamens with tan anthers, and five stamens fused at their bases. The fruit is spherical with a very long beak divided longitudinally into five sections; when ripe (the fruit turns bright red) , the beak splits violently into five strips attached to each other at their distal ends, flinging the seeds far from the parent plant. Carolina crane's-bill has white to pinkish flowers with sepals longer than the petals; cut-leaved crane's-bill (Geranium dissectum) has deep pink to purple flowers with sepals the same length as the petals.

Geranium

Geranium carolinianum

Carolina crane's-bill [Blooms: May-Jun]

Cut-leaved crane's-bill's very attractive flowers occur in pairs. The base of the flower is covered by five green sepals the same length as the petals, covered externally in glandular hairs; the tips of the sepals are drawn out into a short (1-2 mm) awn that is scarlet-tipped. The five petals are a deep pink to purple in color; there are five pink stamens with purplish-yellow anthers; the five styles produce a deep pink, star-shaped stigma at their tips. The fruit consists of five hairy spheres around the base of an elongate "crane's bill" which splits explosively when ripe into five strips attached at their distal ends, flinging the seeds far and wide. Carolina crane's-bill (Geranium carolinianum) has white to pinkish flowers with sepals longer than the petals; cut-leaved crane's-bill has deep pink to purple flowers with sepals the same length as the petals.

Geranium

Geranium dissectum

cut-leaved crane's-bill [Blooms: May-Jun]

Wild geranium flowers are about 1.5 " across; they have five spindle-shaped, green sepals with a short red-tipped awn at their tips and five purplish-pink petals, twice the length of the sepals, that are egg-shaped with broady rounded tips and have darker fine radiating lines that function as necter guides. The ten stamens have pale yellow anthers; the single pistel has five carpels that splay at the tip of the pistil into a starfish shape. The anthers produce pollen while the five styles' stigmas remain pressed together; after the anthers are spent, the stigmas separate. The fruit is a candle-shaped, cylindrical structure with a sharp tip. The carpels build up tension as they dry until they spontaneously snap near their base (above the sepals); as the carpel violently curls upward, it flings a single seed considerable distances like a tiny catapult.

Geranium

Geranium maculatum

wild geranium [Blooms: Apr-Jun]

American hops male and female flowers occur on separate plants. Actual female (pistillate) flowers occur in tight clusters ("aments") 3/4" long of 10-50 flower pairs on a stalk that arises from a leaf axil, each pair subtended by a bract; each flower has two long, thin styles. Male flowers have five pale green spreading sepals and five short, banana-shaped stamens. The fruit is a cone-like structure of overlapping bracts (originally present at the base of the female flowers) that surround the seeds; it is (obviously) found only on the female plants.

Humulus

Humulus lupulus

American hops [Blooms: Jul-Sep]

Giant St. John's wort stems and branches terminate in clusters (cymes) of 1-5 flowers 2-2.5" across; the central bud opens first. Giant St. John's wort has the largest flower of all the St. John's worts found in Illinois. Each flower has five green sepals 1/3 the length of the petals; five bright yellow, often twisted, petals; more than 100 yellow stamens with yellow anthers; and a yellow-green pistil with five distinct styles fused at their bases, each with red stigmas at their tip. Five carpels are present in the flask-shaped ovary. The fruit is a five-chambered, bullet-shaped structure up to 1.25" long and 1/2" wide, initially green, turning brownish-black with maturity; the capsule is topped with the remnants of the (five) styles and contains numerous lozenge-shaped, 1 mm long, black seeds. (When fully mature and with appropriate magnification, the seeds look like ears of corn.) Note in particular the very large (2") flowers and the five styles on the pistil of giant St. John's wort — most other Hypericum spp. have either one or three styles. Kalm's St. John's wort also has five styles, but that is a much smaller and woody plant with narrower leaves and much smaller flowers.

Hypericum

Hypericum ascyron

giant St. John's wort [Blooms: Jun-Aug]

Kalm's St. John's wort is a 1-3 ' tall shrub, largely restricted to the Great Lakes basin of the U.S. and Canada; it is formally listed as "critically endangered" in Illinois (but is quite common in Jackson Park). The flowers occur in clusters (corymbs) of 3-7. Individual flowers are 1-1.25" across; they have five light green, lance-shaped sepals half the length of the petals, five spreading golden-yellow petals, 150-200 stamens with yellow anthers, and a five-lobed yellow ovary with five (partially or completely fused) styles. The ovary often is markedly five-lobed. The fruit is a teardrop-shaped capsule resting on the five widely-spread sepals containing five (occasionally four) carpels; the capsules are initially green, then turn bright red, then finally brown as the numerous black, oblong seeds mature. Woody lower branches and the strongly five-lobed pistil and fruit are distinguishing characters that separate this species from other Jackson Park St. John's worts.

Hypericum

Hypericum kalmianum

Kalm's St. John's wort [Blooms: Jun-Aug]

Common St. John's wort flowers are ~3/4" across, with five green sepals, five oblong yellow petals, three widely-spreading styles (and three carpels) with scarlet stigmas on top of a globular yellow ovary, and numerous (45-85) stamens with yellow anthers. The filaments of the stamens fuse into three groups near their bases. Unique among the St. John's worts in Illinois, common St. John's wort has petals with tiny black dots (glands full of essential oils) that are restricted to the petal margins. (Hypericum punctatum, spotted St. John's Wort, also has black dots on the petals but, in that species, they extend to the interior of the petals.) These black glands may also occur sparsely on the anthers. The fruit is a three-chambered, bullet-shaped structure 1/4" long, initially green, turning reddish-brown with maturity; the capsule is topped with the remnants of the (3) styles and contains numerous seeds. Common St. John's wort contains chemicals that may interact adversely with a number of common pharmaceuticals despite its widespread use in traditional medicine and may be toxic to livestock in large doses.

Hypericum

Hypericum perforatum

common St. John's wort [Blooms: Jun-Aug]

Shrubby St. John's wort is, as the name says, "shrubby;" the "prolificum" part refers to the exceptionally numerous stamens. The upper stems and axils of the two upper pairs of leaves produce clusters of 3-7 flowers. Flowers are ~1" across, with five green sepals much shorter than the petals, five yellow petals, 150-500 stamens, and a pistil with three styles united at the base and appressed along their lengths. The fruit is a capsule <1/2" long, cone shaped and tapering to the tip, with the tips of the three styles persistant, not lobed but bluntly triangular with three compartments internally (corresponding to the three carpels of the ovary). Hypericum prolificum and Hypericum kalmianum both have woody lower branches (the only Hypericum sp. that do) and are very similar vegetatively, but H. kalmianum produces a seed capsule with the remnants of five styles and has five internal compartments while H. prolificum produces seed capsules bearing the remnants of three styles and has three internal compartments.

Hypericum

Hypericum prolificum

shrubby St. John's wort [Blooms: Jun-Aug]

Round-fruited St. John's wort flowers are 1/2-3/4" across, with five (sometimes four) green sepals shorter than the petals, five rounded, bright-yellow petals with curled margins and tips, 45-85 yellow stamens with orange anthers, and a slender, flask-shaped pistil with three styles fused at their bases bearing tiny stigmas. The fruit is globular with a long, tapering neck, not a lobed bullet-shape as in other Hypericum. Descriptions of this species say it has three styles, but the populations in Jackson Park typically have flowers with what is apparently single style but close inspection (especially of older flowers) show actually has three styles, closely appressed. The styles separate at their tips late in blooming or early in the development of most fruits.

Hypericum

Hypericum sphaerocarpum

round-fruited St. John's wort [Blooms: Jun-Jul]

Wood nettle plants may be either monoecious (separate male and female flowers on the same plants) or unisexual (only male or only female flowers). Male flowers are produced from branching cymes 4" long that arise from the leaf axils; female flower are produced from branching cymes, also 4" long, localized near the apex of the stem. Male flowers are small (1/8" across), consisting of five narrow, greenish-white sepals and five stamens; there are no petals but there is a vestigial pistil. Female flowers are about the same size (1/8" across) with four green sepals (two larger, two smaller) that look like tiny leaves with undulating edges and an ovary with a long, white, vertically-oriented J-shaped style that tapers to a point. The female flowers are wind-pollinated. The fruit is circular in outline but very flattened, green turning black with maturation, on a short winged stalk; the remains of the style are attached at the free end of the fruit.

Laportea

Laportea canadensis

wood nettle [Blooms: Aug-Sep]