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Downy serviceberry is a shrub or small tree 10-30' tall that blooms very early in the spring, before (most) leaf emergence; this is the most common Amelanchier sp. in Illinois. Downy serviceberry flowers bloom in a cluster of 5-12 before or early in leaf emergence. (Emerging leaves are folded and bronze-tinged.) Flowers are 1" across with a short, light green, a hairy calyx with five narrow triangular teeth 1/3 the length of the petals that are strongly bent back towards the stem; five narrow, oblong white petals; 15-20 stamens with creamy yellow anthers; a hairless green ovary; and a green pistil with a single five-parted style. Downy serviceberry flowers can be easily distinguished from Wiegand's shadbush (Amelanchier interior); the former has a hairless ovary while the latter has an ovary whose top is densely covered with wooly hairs. The very hairy undersides of downy serviceberry leaves are also a good clue to its identity, although other Amelanchier spp. also have (less) hairy leaves.

Amelanchier

Amelanchier arborea

downy serviceberry [Blooms: Apr-May]

Wiegand's shadbush (aka, serviceberry) is a shrub or small tree up to 10m tall, uncommon in Illinois and restricted to the northeastern portion of the state. The flowers bloom in clusters of 6-12 simultaneously with leaf emergence. (Emerging leaves are folded and bronze-tinged.) The flowers are 1" across with a short, light green, hairy calyx with five narrow triangular teeth 1/3 the length of the petals, strongly bent back towards the stem; five narrow, oblong white petals; 18-20 stamens with creamy yellow anthers; a characteristic green ovary densely hairy on the top; and a green pistil with a single five-parted style. Wiegand's shadbush flowers can be easily distinguished from downy serviceberry (A. arborea); the former has an ovary whose top is densely covered with wooly hairs while the latter has a hairless ovary.

Amelanchier

Amelanchier interior

Wiegand's shadbush [Blooms: Apr-May]

Sharp-lobed hepatica is an early-blooming, woodland wildflower with distinctive 3-lobed, superficially palmate, variegated basal leaves on long petioles. The flowers are 1" across, borne on naked, reddish, hairy stalks ~4" long. Flowers consists of 5-11 (typically 6) blue, white, or lavender, oblong petals (actually, sepals), copious white stamens, and numerous green carpels; behind the flower are 3 reddish, hairy bracts shorter than the petals. ITIS considers Hepatica acutiloba a junior synonym of Anemone acutiloba; the USDA Plants Database, IUCN Red List, and NatureServe Explorer considers H. acutiloba as a junior synonym of Hepatica nobilis. All agree it is "sharplobed hepatica." The roundlobed hepatica (which is either a variety of sharplobed hepatica or a separate species, depending on which authority you prefer) is identical except that the lobes on the leaves are smoothly rounded.

Anemone

Anemone acutiloba

sharp-lobed hepatica [Blooms: Apr]

The petals (actually, sepals) of Canada anemone flowers are rounded; the pistillate cone in the center of the flower is approximately hemispherical and less than 10% of the flower width. The fruit is a round cluster of flattened seeds. The five-lobed leaves of Canada anemone are superficially similar to those of wild geranium (Geranium maculatum) but are sessile, not borne on petioles. Canada anemone is the commonest flower in Jackson Park in the late spring and summer.

Anemone

Anemone canadensis

Canada anemone [Blooms: May–Oct]

Thmbleweed flowers are borne on long (1-2') stalks; each flower is about 3/4" across with 5 pointed white petals-like sepals that often remain partially closed; the green pistillate cone in the center of the flower is about twice as long as it is wide (i.e., a tall gumdrop) ~20% of the flower diameter. A. canadensis may also have pointed petals, but the cone in the center of the flower is hemispherical (a short gumdrop). Thimbleweed (A. cylindrica) is best distinguished from tall anemone (A. virginiana) by the shape of the leaflets — A. cylindrica has leaflets with a wedge-shaped base with the lobes radiating out from the base, while A. virginiana has a rounded leaflet base with toothed distal margins.

Anemone

Anemone cylindrica

thimbleweed [Blooms: Jun-Jul]

Wood anemone produces slender green, hairy stems that bear either alternate leaves or (more typically) a whorl of three compound leaves at the apex of the stem; the 5 cm tall flower stalk arises from the center of the whorl. The flower stalks each bear a single white (sometimes pink) flower 1" across with 4-9 petal-like sepals and 30-60 stamens with white anthers surrounding numerous simple pistils.

Anemone

Anemone quinquefolia

wood anemone [Blooms: Apr–May]

Tall anemones have leaves on long petioles (like A. cylindrica). The petals (actually, sepals) of the flowers are pointed (like A. cylindrica); the pistillate cone in the center of the flower is approximately hemispherical and >1/3" across, about 20% of flower diameter. Thimbleweed (A. cylindrica) is best distinguished from tall anemone (A. virginiana) by the shape of the leaflets — A. cylindrica has leaflets with a wedge-shaped base with the lobes radiating out from the base while A. virginiana has a rounded leaflet base with toothed distal margins.

Anemone

Anemone virginiana

tall anemone [Blooms: Jun–?]

Field pussytoes flowerheads are either pistillate (female) or staminate (male), both about 8 mm long, both looking like a compact tuft of white hairs. The very similar plantain-leafed pussytoes (A. plantaginifolia) looks much the same but has basal leaves with three main veins (best viewed from the underside) rather than one.

Antennaria

Antennaria neglecta

field pussytoes [Blooms: Apr-May]

Plantain-leafed pussytoes is a short (6" tall) plant. The basal leaves are 2" wide and 3.5" long, spoon-shaped with long petioles, grayish green, with 3-5 conspicuous main veins; the lower surface is densely covered with appressed hairs and is shiny white. Individual plantain-leafed pussytoe plants bear either male or female flowers exclusively. Flowerheads are short (<1/2" long) and composed exclusively of white disc florets surrounded by a layer of phyllaries; female florets are fluffy white from the profusion of styles (looking a bit like Q-Tips) while male florets show tubular, brownish anthers. Asexual reproduction may produce colonies of exclusively male or female plants. The similar field pussytoes has basal leaves with only a single (rather than 3-5) main veins.

Antennaria

Antennaria plantaginifolia

plaintain-leafed pussytoes [Blooms: Apr-May]

Spectacular and unmistakable red and yellow, columbine's bell-like flowers hang aperture down from an arching flower stalk; the four elongate, parallel spurs point up while the stamens and style emerge from the bottom of the flower. This is the only columbine native to Illinois.

Aquilegia

Aquilegia canadensis

red columbine [Blooms: Apr-Jun]

An ornate pink flower with multiple levels of petals above a central core of projecting yellow stamens. This variant of Aquilegia vulgaris ("stellata" commercially called 'Nora Barlow') is a genetic variant that produces multiple stacked flowers (like the difference between a wild rose and commercial roses).

Aquilegia

Aquilegia vulgaris

common columbine [Blooms:May-Jun]

Japanese angelica tree may be mistaken for the (native) devil's walking stick, Aralia spinosa. However, the Japanese angelica tree (A. elata) has shorter (although quite substantial) compound leaves, sessile leaflets directly attached to the petiolule, a smaller inflorescence (about 2' tall rather than over 3'), and shorter, less intimidating spines on the trunk. Leaf venation (best viewed from the underside) is the best way to differentiate the two. In devil's walking stick, the pinnate leaf vein tips curve to form a sub-marginal vein parallel to the leaf margin. In the Japanese angelica tree, the leaf veins extend all the way to the margins of the leaf.

Aralia

Aralia elata

Japanese angelica tree [Blooms: Jul/Aug–?]

Spikenard is superficially similar to devil's walking stick (Aralia spinosa) but lacks the spiny leaves and stem of the latter. Both produce a terminal inflorescence of flowers (20+ ft. up). Unlike devil's walking stick, the flowers of spikenard are perfect; i.e., they have both male (stamens) and female (a stigma) parts. In this photo, both flower buds and flowers with prominent stamens are apparent.

Aralia

Aralia racemosa

spikenard [Blooms: Jul-Aug]

A small, somewhat shrubby tree up to 25' tall, although half that height is more common in Jackson Park (which is near the northern limit of its range). Devil's walking stick produces a terminal inflorescence of flowers (20+ ft. up). Flowers are small (1/4" long), white and are produced in umbels at the top of the tree. Devil's walking stick has flowers that are either male (bearing stamens) or female (bearing styles). The male flowers of devil's walking stick have prominent stamens and five white, triangular petals; the female flowers (shown here) look like rounded green buds with five stout styles emerging from the distal end.

Aralia

Aralia spinosa

devil's walking stick [Blooms: Aug-Sep]

Burdock has thistle-like, composite flowers with lavender to purple (rarely, white) disc florets but no ray florets; the surrounding bracts are green and strongly hooked.

Arctium

Arctium minus

burdock [Blooms: Jul-Oct]

Two thyme-leaved sandwort flowers, with leaves clearly visible on the stem on the left of the image. Easily overlooked as just another chickweed, thyme-leafed sandwort's petals are not deeply notched like chickweeds. The stems are 6-10" tall, erect or sprawling, dark purple, and covered with fine hairs. Tiny (4 mm) white flowers on 1/4" pedicels with backward-pointing hairs; flowers have five pointed, white, oblong petals; five hairy green sepals longer than the petals; ten white stamens with magenta anthers; a green central ovary; and three white styles. An exotic from Europe that prefers disturbed areas with minimal other vegetation.

Arenaria

Arenaria serpyllifolia

thyme-leaved sandwort [Blooms: Apr-Jun]

Red chokeberry is a 6-12" tall shrub with multiple stems. Flowers are white with red tinge on the tips of the 5 petals; each flower is ~1" in diameter.

Aronia

Aronia arbutifolia

red chokeberry [Blooms: Apr-May]

Black chokeberry flowers occur in clusters of 7-12 near the margins of the shrub. Each flower is ~1/2" across with a reddish-green calyx with 5 short triangular lobes, 5 white, spoon-shaped, non-overlapping petals with rounded tips and a narrow base, 16-20 stamens with pink to rose-colored anthers, and 5 pale green styles, fused at their bases. The red glands on the upper leaf midvein and pink to rose-colored stamens are diagnostic of black chokeberry.

Aronia

Aronia melanocarpa

black chokeberry [Blooms: May-?]