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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]

Dame's rocket flowers occur in clusters (racemes) of up to 30. Each flower is 3/4-1" across and long, with a long, narrow, tubular, pinkish-green calyx composed of four long narrow sepals. The calyx opens through a narrow throat into four rounded, pinkish-purple (sometimes white) petals; the six pale yellow stamens and the multiple styles poke to various degrees out of the throat. Stems, leaves, pedicles, and the flower calyxes are all downy or hairy. The fruits are long (up to 4"), narrow, ascending, downy cylinders (siliques, typical of mustards) filled with flattened, oblong seeds. The flowers are very phlox-like, but phlox flowers have five petals, and dame's rocket only has four; phlox leaves are opposite on the stem (not alternate) and are narrower.

Hesperis

Hesperis matronalis

dame's rocket [Blooms: Apr-May]

Halberd-leaved rose-mallow is a striking wild hibiscus, usually found near water, whose stems can get 6' tall. Flowers arise from leaf axils, are trumpet-shaped, up to 5" across, with five rounded, partially overlapping white to pink petals; a central columnar reproductive structure covered in creamy-white stamens (with reddish-tan anthers) in whorls, and a terminal divided style with five recurved tips, each bearing a stigma shaped like the head of a pin. Behind the corolla is a green calyx with five lobes, and ~12 rod-like, curved, green bractlets below the calyx that taper to sharp points. The throat of the flower is a deep reddish-purple or rose pink. Seed pods form within the persistant sepals; the seed pod is divided into five sections filled with fuzzy brown seeds. The three-lobed (halberd-shaped) or five-lobed (maple leaf shaped) leaves distinguish this species from other rose-mallows. (Only swamp rose-mallow, Hibiscus moscheutos, also occurs in Jackson Park.)

Hibiscus

Hibiscus laevis

halberd-leaved rose-mallow [Blooms: Jul-Aug]

Swamp rose-mallow is a wild hibiscus that prefers wet habitats; the stem can get up to 7' tall. Flowers arise from leaf axils and are trumpet-shaped, 4-6" across with five pink or white petals (sometimes with a reddish-purple throat); and, in the center of the flower, a stout cream colored column that bears both whorls of white stamens with yellow anthers and a white style divided into five upcurving parts, each with a pin-head shaped stigma. Behind the corolla are five light green sepals and 12 awl-like 1" long bracts that curve forwards. This is the more variable of the two local rose mallows; it has white or pink flowers which may or may not have a reddish-purple throat (all are now considered the same species).

Hibiscus

Hibiscus moscheutos

swamp rose-mallow [Blooms: Jul-Aug]

Common morning glory is a vine up to 10' long with alternate, heart-shaped (never lobed), smooth-margined, almost as wide as long. The stem is green or reddish-purple, covered with long hairs; it twines around adjacent vegetation and objects. Cymes of 1-5 flowers arise from some leaf axils; they sit at the tip of about 4" long pedicels. The flowers are 2-3.5" wide, funnel-shaped, usually deep purple or pink, less commonly blue or white, a single style with a three-lobed stigma, and five stamens. Sepals are relatively short, hairy, and triangular unlike ivy-leaved morning glory (I. hederacea), where the sepals are long and narrow. Other morning glories (Ipomoea sp.) usually have lobed leaves; the superficially-similar bindweeds usually have arrowhead-shaped leaves, not heart-shaped. Common morning glory has sepals that are short and triangular, unlike ivy-leaved morning glory where the sepals are relatively very long and narrow. Common morning glory is native to Mexico; it was introduced to England by 1621, then introduced from England to North America around 1700 as an ornamental (Fang et al., 2013), where it rapidly escaped cultivation.

Ipomoea

Ipomoea purpurea

common morning-glory [Blooms: Aug-Sep]

Motherwort is a naturalized exotic from Eurasia with stems up to 5' tall (more commonly 3-4'); branches occur near apex, if they are present at all. The flowers are sessile; they occur in whorls just above a pair of opposite leaves in the upper half of the plant, almost completely covering the stem. Individual flowers are about 3/8" long, two-lipped and VERY hairy on the outer surfaces with profuse long, white hairs; the upper lip is reflected backwards and unlobed, while the lower lip is divided into three lobes. The lips are white or light pink with purple spots on the lower lip and purple mottling on the upper lip. Four stamens with purple anthers protrude about half way up the upper lip; there s a single style with a two-lobed stigma that is located between the two longest stamens. The stubby, tubular calyx has five very sharp lobes/spines lending a touch of danger to the flowers; after fertilization, the calyx holds four nutlets, each containing a single seed. Motherwort was introduced from Europe (where it was previously introduced from Asia) primarily as a medicinal herb; it is now considered invasive. Motherwort could possibly be confused with field mint (Mentha arvensis) but field mint lacks the distinctive three- or five-lobed angular-cleft leaves of motherwort and has boldly-protruding stamens that are lacking in motherwort.

Leonurus

Leonurus cardiaca

motherwort [Blooms: Jun-Aug]

Cylindrical blazing star is a more open plant than the other Jackson Park blazing stars, with the flowerheads relatively widely spaced along the 2-4" long racemes that are perched atop a 1-1.5' tall, unbranched stem. The showy flowerheads are pink or purplish-pink, about 1/2-3/4" in diameter, sessile or held on up to 3/4" stalks, with 15-25 disk flowers and no ray flowers; the base of the flowerheads is covered with 5-7 layers of scale-like, overlapping bracts with a sharp tip that together form a slim cylinder ~3/4" long and 1/3" diameter. The disk florets are tubular with five recurved triangular flaps at their apex; a pinkish white style, surrounded at its base by the five closely-packed yellowish-brown anthers and divided distally into two long filaments. Cylindrical blazing star appears to prefer dryer, well drained soils. The Jackson Park blazing stars bloom in the order cylindrical, prairie, rough, marsh, and Rocky Mountain; in relative abundance, rough is the most common, followed by cylindrical, prairie, marsh, and Rocky Mountain blazing stars. Quick key to the Jackson Park blazing stars: bracts covering base of the flowerhead are (1) sharply pointed (-> cylindrical), (2) recurved away from flower, flaring (-> prairie), (3) tip round, closely appressed (-> marsh), (4) margins with tiny teeth, rolled under (-> rough if flower stalk is very short, Rocky Mountain if flower stalk about same length as flowerhead).

Liatris

Liatris cylindracea

cylindrical blazing-star [Blooms: Jul-Aug]

Prairie blazing star's stem ends in a spike of composite, purple flowerheads 1/4-1/2" across; pinkish-red bracts cover the underside of the flowerheads, tapering to a fine tip that dramatically curls away from the flowerhead (like the scales on a dry pine cone). (No other blazing stars have such recurved bracts.) Each flowerhead has 5-10 disc florets that are tubular, 7-10 mm long, with five lobes at the apex forming a prominent star shape. A hairy, divided style protrudes well beyond the apex of the corolla; the base of the style is surrounded by the 3 mm long, reddish-brown anthers of the five stamens. Prairie blazing stars prefer well-watered areas. The Jackson Park blazing stars bloom in the order cylindrical, prairie, rough, marsh, and Rocky Mountain; in relative abundance, rough is the most common, followed by cylindrical, prairie, marsh, and Rocky Mountain. Quick key to the Jackson Park blazing stars: bracts covering base of the flowerhead are (1) sharply pointed (-> cylindrical), (2) recurved away from flower, flaring (-> prairie), (3) tip round, closely appressed (-> marsh), (4) margins with tiny teeth, rolled under (-> rough if flower stalk is very short, Rocky Mountain if flower stalk about same length as flowerhead).

Liatris

Liatris pycnostachya

prairie blazing-star [Blooms: Jul-Aug]

Marsh blazing star flower spikes are 4-18" long extensions of the main stem, crowded with pinkish-purple flowerheads facing in all directions. Individual flowerheads are about 8 mm across; ray florets are absent and the 4-10 disc florets dominate. The corolla of a disc floret is tubular with five lance-shaped apical lobes; the divided style extends well outside the tubular corolla, surrounded at its base by five tightly packed stamens. The base of the flowerhead is covered with overlapping, flattened, elongate-oval bracts with rounded tips. Marsh blazing star is similar to prairie blazing star in appearance, but the bracts of prairie blazing star are highly recurved (like the scales on a dry pine cone). Quick key to the Jackson Park blazing stars: bracts covering base of the flowerhead are (1) sharply pointed (-> cylindrical), (2) recurved away from flower, flaring (-> prairie), (3) tip round, closely appressed (-> marsh), (4) margins with tiny teeth, rolled under (-> rough if flower stalk is very short, Rocky Mountain if flower stalk about same length as flowerhead).

Liatris

Liatris spicata

marsh blazing-star [Blooms: Aug]

Tatarian honeysuckle's flowers arise from upper leaf axils in pairs on a 3/4-1" long pedicles. Individual flowers are 3/4" (both long and across); there is a short (1/4") green calyx with five lobes; a pink to rosy-pink tubular corolla that flares to produce five narrow, spreading lobes — the middle two lobes on the upper lip of the corolla are vertical and fused at their base, the other two are spreading; the sole lobe on the lower lip is bent down. Protruding from the throat of the corolla are five stamens with white filaments and yellow anthers and a slender, white style with a green, dome-shaped stigma. The fruit is a pair of 1/4" berries that turn bright red on maturity. Of the exotic honeysuckles (amur, Morrow's, tartarian) in Jackson Park, tartarian honeysuckle is the only species that is virtually hairless and the only one with reddish (as opposed to white) flowers. Please don't plant this species in your garden — too often, it escapes.

Lonicera

Lonicera tatarica

tatarian honeysuckle [Blooms: Apr-May]

Winged loosestrife is a native species that has a central stem up to 3' tall, much more modest that its notorious cousin, purple loosestrife. The stem is four-sided, narrowly winged, and largely hairless; wings run along the stem but are interrupted at the leaf nodes. The inflorescence is a spike up to 1.5' long; the flowers develop singly or in pairs from the axils of bracts on the inflorescence. Each flower is pale lavender or purple and smaller than the flowers of purple loosestrife (1/4-1/2") but otherwise superficially similar — pale purple or lavender, six wrinkled petals with a medial purple stripe, six stamens. The light green, narrow calyx is about as long as the petals, has six (not five) lance-shaped teeth, and bold longitudinal stripes. The style may or may not protrude from the corolla — the flowers are distylous so the styles may either lie just inside the flower throat or protrude well outside; the style has a fuzzy, green, globular stigma. The fruit is a capsule that develops in the remnants of the calyx. Winged loosestrife prefers wet soils and is a less showy plant than purple loosestrife, but it is a native plant that plays nicely with its neighbors.

Lythrum

Lythrum alatum

winged loosestrife [Blooms: Jun-Aug]

Purple loosestrife plants are 2-5' tall. The stems branch frequently, are square in section or ridged, and are very hairy except where the stem is woody. The very showy flower spikes can be up to 20" long. Individual flowers are 1/2-1" wide that are sessile or on very short stalks; there are 5-7 (usually six) purple, wrinkled petals with a dark purple line near their base. (Imagine purple crepe paper.) The long tubular calyx is yellow-green, ridged, and hairy, with five long, narrow teeth at the distal end. Purple loosestrife is "tristylous" — it exhibits three discrete flower morphs that differ in the relative lengths of the stamens and style. Each plant bears flowers of only a single morph. Each morph has two different lengths of stamens — pistil short, stamens long AND stamens intermediate in length; pistil intermediate in length, stamens short AND long; and pistil long, stamens short AND intermediate in length. Tristyly presumably minimizes self-fertilization. Purple loosestrife is a very aggressive, invasive species which crowds out other species. Another invasive which is also called purple loosestrife, Lythrum virgatum, has similar flowers but the leaves narrow towards their base. (L. virgatum is not known to occur — yet — in Illinois.) Do not confuse purple loosestrife with the native winged loosestrife (Lythrum alatum) which has winged stems, smaller flowers (1/2"), hairless foliage, and solitary flowers in leaf axils. It's not as striking a plant as purple loosestrife, but it plays better with its neighbors.

Lythrum

Lythrum salicaria

purple loosestrife [Blooms: Jun-Sep]

Prairie crabapple produces clusters of 2-6 flowers on the tips of the spurs and twigs. The flowers are 1-2" across with a green, hairy, cup-shaped calyx with five narrow, triangular teeth; five white or (usually) light-pink, oval petals tapering to very narrow bases; 10-20 stamens with yellow anthers; and five robust styles. The fruits are typical crabapples about 1-1.5" across with the calyx persistent, greenish-yellow and waxy when mature; the flesh is firm but sour-tasting.

Malus

Malus ioensis

prairie crabapple [Blooms: Apr-May]

Smallflowered gaura is a spindly, usually unbranched plant that gets 2-6' fall, much of that the flower spike. The stem is round in section, light- to reddish-green, and covered with fine hairs. The leaves are alternate, 2-5" long and 1/4-1" across, lance-shaped, and sessile. The apex of the stem gives rise to a narrow spike of small flowers 1/2-2.5' long. Flowers open from the base of the spike towards the tip with relatively few open at any one time. Individual flowers are about 1/4" across. They consist of four sepals reflected back along the elongated, cylindrical, light-green or red flower stalk/ovary, four spreading white or pink petals, eight stamens, and a long style with a X-shaped (or four-lobed) stigma. The flowers are said to open in the evening and close in the morning. The seed capsules develop from the ovary; they are about 9 mm long. The flowers and flower spike of smallflowered gaura are quite distinctive and unlikely to be confused with any other species.

Oenothera

Oenothera curtiflora

smallflowered gaura [Blooms: Jul-Sep]

As the name suggests, biennial gaura is a biennial. In its first year biennial gaura develops a dense, flat basal rosette; in its second year, multiple stems shoot up from the basal rosette, branching frequently and reaching 3-7' tall. The flower spikes are 4-8" long with flowers opening from the bottom to the top. Each flower is open and airy, 1/2" long and wide, with four white or pink, spoon-shaped, petals deployed around the upper quadrant of the flower; eight long white stamens with yellow anthers and a single long white style with a yellow, X-shaped, stigma emerge at right angles to the fan of petals. Behind the petals is a red or green, hairy, tubular calyx with four sepals whose tips are reflected backwards. The fruits lie on the flower spikes behind the open flowers; they are diamond- or spindle-shaped with a flat-to-conical tip and four large ribs running longitudinally and are covered with fine hairs. Oenothera gaura is almost indistinguishable from large-flowered gaura (Oenothera filiformis, a.k.a., Gaura longiflora), but the latter has larger flowers and hairs on the stems that are curled against the stem (as opposed to straight hairs); I've not identified large-flowered gaura in Jackson Park.

Oenothera

Oenothera gaura

biennial gaura [Blooms: Jul-Sep]

Creeping smartweed is another weedy exotic, but its charm increases as you look closer. The flower spikes are 1.5" long and <1/4" wide; they are covered with tiny (~1/8" long) flowers with five pink tepals, only a few of which are open at any one time. (Petals are absent.) There are five stamens with pink or yellow anthers and three styles hidden within the flower; they are visible only with difficulty. At the base of each flower is a small membranous sheath with bristles as long or longer than the flowers (not present on all flowers). After fertilization, a three-angled seed that tapers to a point on each end develops nestled in the tepals. This is an Asian species that was introduced to North America around 1910 near Philadelphia and reached Illinois in the 1940's; it strongly prefers wet soils. Creeping smartweed resembles lady's-thumb (Persicaria maculosa), but creeping smartweed's sprawling habit and the long bristles associated with the flowers are distinctive.

Persicaria

Persicaria longiseta

creeping smartweed [Blooms: May-Oct]

Lady's-thumb is an exotic, native to Europe, but has a long history in North America — it was first reported from the Great Lakes in 1843. Flower spikes (racemes) are 1/2-1.5" long and densely covered with tiny (1/8" long) pinkish-white flowers; flower color is quite variable, even within a single flower spike. The flowers are "shy" and often open only at the tips of the 4 or 5 sepals (there are no petals); both the six stamens and the single style (divided into three towards the distal end) remain hidden. Seeds are black; they develop singly within the persistent sepals and remain largely hidden by the sepals; they can be found on flower heads still blooming. Lady's-thumb prefers wet habitats.

Persicaria

Persicaria maculosa

lady's-thumb [Blooms: Jun-Sep]