Asterids Species Names

Ipomopsis aggregata

Polemoniaceae

Biennial; basal rosette first year, tall flowering stalk second year; often abundant after fire

Alternate, pinnately divided into narrow linear segments; prickly-tipped; rosette leaves larger

Salverform (long tube, flaring lobes); corolla scarlet (rarely pink or white); tube long; 5 lobes; stamens 5; style 3-branched; ovary superior; hummingbird-pollinated

Dry to mesic slopes, open forest, disturbed areas; foothills to subalpine; common post-fire

Gentiana affinis

Gentianaceae

Perennial herb from a woody caudex; stems erect; late-season bloomer

Opposite, lanceolate to ovate, margins entire; sessile

Tubular-campanulate; corolla blue to blue-violet; 5 lobes; plaits between lobes; calyx 5 lobed; stamens 5; ovary superior; capsule

Moist meadows, open slopes, streambanks; montane to alpine

Frasera speciosa

Gentianaceae

Monocarpic perennial (hapaxanthic); basal rosette for 20–80+ years, then a single massive flowering stalk (1–2m) and death; populations bloom synchronously every several years (mast-seeding)

Large basal rosette; cauline leaves opposite to whorled in 4s, reducing upward

In whorled clusters along the stem; corolla 4-lobed; petals greenish-white with purple spots; each petal with a fringed gland pit (nectary); calyx 4-lobed; stamens 4; ovary superior; capsule

Moist mountain meadows, open forest; montane to subalpine

Gentianopsis thermalis

Gentianaceae

Annual or biennial herb; protected wildflower; thermalis refers to association with hot spring vicinity

Opposite, linear to spatulate, margins entire; sessile

Tubular to funnel-shaped; corolla blue to blue violet; petal lobes with deeply fringed/laciniate margins; 4-lobed; stamens 4; ovary superior; capsule

Wet meadows, streambanks, springs; montane to alpine

Apocynum androsaemifolium

Apocynaceae

Perennial herb from rhizomes; stems branching; milky latex throughout; leaves droop characteristically in heat

Opposite, ovate to elliptic, 3–8cm, margins entire; drooping; dark green; glabrous

Campanulate; corolla white with pink stripes inside; 5 lobes, reflexed; calyx 5-lobed; stamens 5; fruit paired follicles; seeds with tuft of silky hairs for wind dispersal

Dry to mesic forest edges, roadsides, disturbed areas; foothills to montane

Asclepias speciosa

Apocynaceae

Perennial herb from rhizomes; stout; milky latex; clonal; critical host plant for Monarch butterflies (Danaus plexippus)

Opposite, broadly ovate to oblong, 8–15cm; densely pubescent; sessile to short-petiolate; large

Highly modified; 5 reflexed petals; corona of 5 hooded appendages, each with a horn projecting inward; central gynostegium (fused stamens + pistil column); pollinia (pollen masses) transferred as a unit; corolla pink-purple; fragrant; fruit a large inflated follicle; seeds silky-plumed

Moist areas, roadsides, streambanks, disturbed areas; plains to montane

Asclepias viridiflora

Apocynaceae

Perennial herb from a deep taproot; stems usually solitary, erect; less showy than most milkweeds; deep-rooted prairie specialist

Alternate to opposite (variable — inconsistently arranged); lanceolate to broadly elliptic; margins undulate; sessile or nearly so

Same milkweed structure; corolla green; corona hoods greenish and lacking horns; fruit a follicle; seeds silky-plumed

Dry grasslands, rocky slopes; plains to foothills; eastern CO

Helianthus annuus

Asteraceae; Heliantheae

Annual herb; stems erect, stout, rough-hairy; ancestor of the cultivated sunflower; native to North America

Alternate (lower sometimes opposite), broadly ovate to cordate, 10–30cm, margins serrate; rough-hairy; long-petiolate; 3-veined from near the base

Heads large; ray florets 17–30, yellow, pistillate; disk florets numerous, tubular, brown to purple-brown; phyllaries ovate with long spreading hairy tips; receptacle flat, chaffy; achene compressed, pappus of 2 deciduous awns

Disturbed areas, roadsides, grasslands; plains; widespread weedy annual

Artemisia frigida

Asteraceae; Anthemideae

Perennial subshrub from a woody caudex; silvery-silky throughout; aromatic; mat-forming; indicator of disturbed or overgrazed range

Alternate, 2–3× pinnately divided into narrow linear segments; densely silvery-silky; very aromatic

Heads small (3–4mm), nodding, in a narrow raceme or panicle; discoid (no ray florets); disk florets yellowish; phyllaries with silvery-hairy margins; wind-pollinated; pappus absent (or vestigial)

Dry grasslands, rocky slopes, disturbed areas; plains to alpine; very widespread

Erigeron speciosus

Asteraceae; Astereae

Perennial herb from a rhizome or caudex; erect; one of the most attractive of the fleabanes

Basal and cauline; basal oblanceolate; cauline lanceolate to elliptic, clasping at base (amplexicaul) — useful field mark; margins entire to remotely toothed; glabrous or sparsely hairy

Heads 1 to several; rays 50–100+, narrow, blue-lavender to violet; high ray count distinguishes Erigeron from Symphyotrichum (asters), which have fewer; disk yellow; phyllaries in 2–3 series, narrow; pappus of bristles

Open forest, meadows, aspen groves; montane to subalpine

Solidago rigida

Asteraceae; Astereae

Perennial herb from rhizomes; stems stout, stiff-hairy

Basal and lower cauline oblanceolate, petiolate; upper cauline sessile, clasping; rough-hairy; thick and stiff; margins entire or toothed

Heads in a flat-topped to dome-shaped corymb — distinguishes this species from most goldenrods, which produce one-sided arching plumes; rays yellow, short (5–8); disk florets numerous; phyllaries rounded; achene with pappus of bristles

Dry to mesic grasslands, open areas; plains to foothills

Liatris punctata

Asteraceae; Eupatorieae

Perennial herb from a corm-like rootstock; stems erect; numerous resin-dotted leaves; flowers open from the top of the spike downward (basipetal — opposite of the usual acropetal pattern) — a teaching character

Alternate, linear, 1–4mm wide, numerous, dotted with resin glands (punctata = dotted); sessile

Heads in a dense spike; discoid (no ray florets); 4–6 disk florets per head; corolla pink-purple, tubular; style branches feathery, long-exserted; phyllaries with spreading to reflexed tips; pappus of plumose (feathery) bristles — distinguishes from most Asteraceae with simple pappus bristles

Dry grasslands, rocky slopes; plains to foothills; eastern CO; defining species of the shortgrass prairie

Arnica cordifolia

Asteraceae; Heliantheae

Perennial herb from rhizomes; usually 2–3 pairs of opposite stem leaves; clonal; glandular-aromatic; one of the most abundant forest wildflowers in CO

Opposite — a key diagnostic character for Arnica within Asteraceae, where alternate leaves are the norm; basal cordate (heart-shaped), long-petiolate (cordifolia = heart-leaved); upper cauline sessile; margins dentate; softly hairy

Head usually solitary; rays yellow, 10–14, tips 3-toothed; disk yellow; phyllaries glandular-hairy; pappus of white barbellate (minutely barbed) bristles; achene

Coniferous forest, aspen groves; montane to subalpine; very abundant

Grindelia squarrosa

Asteraceae; Astereae

Annual to short-lived perennial; stems erect, branching; sticky-resinous throughout; aggressive disturbed-area colonizer

Alternate, oblong to oblanceolate, margins serrate; base clasping/auriculate; resinous-dotted

Heads medium (2–3cm); rays yellow, 25–40; disk yellow; involucre conspicuously sticky-white-resinous and phyllaries strongly reflexed (squarrose — curling backward and outward — the "curlycup" and squarrosa both refer to this); achene with pappus of 2–8 deciduous awns; the resinous reflexed phyllaries are unmistakable

Dry disturbed areas, roadsides, overgrazed pastures; plains to montane; weedy

Gaillardia aristata

Asteraceae; Heliantheae

Perennial herb from a taproot; stems erect, glandular-hairy; one of the showiest native wildflowers on the CO plains and foothills

Alternate; basal petiolate, oblanceolate, margins toothed to pinnately lobed; cauline sessile; hairy

Heads large (5–8cm); rays yellow, often with a red-purple base creating a bicolored target pattern (variable); ray tip 3-lobed; disk florets red-brown to purple; chaffy bracts on receptacle persistent, tips bristle-like (aristata = awned, referring to these tips); pappus of 6–10 awned scales; achene

Dry grasslands, roadsides, open areas; plains to montane; very widespread

Lomatium orientale

Apiaceae

Perennial herb from a taproot; low-growing; among the earliest-blooming wildflowers in CO — flowers when snow is still possible; orientale = eastern

Basal (or nearly so), 2–3× pinnately compound; ultimate segments narrow; glabrous; petioles sheathing at base

Tiny, in compound umbels; petals white and dark purple/maroon mixed on the same plant — the "salt-and-pepper" appearance is diagnostic and gives the common name; calyx teeth minute; stamens 5; ovary inferior; fruit a schizocarp, mericarps with thin lateral wings

Dry rocky slopes, grasslands; plains to foothills; eastern CO; early spring

Heracleum maximum

Apiaceae

Perennial herb; extremely large (1–2.5m); one of the biggest herbaceous plants in CO; sap is phototoxic — contact followed by UV exposure causes severe blistering (phytophotodermatitis); handle with care

Very large (30–60cm), palmately 3-lobed or compound; leaflets broadly ovate, lobed and toothed; petioles hollow, strongly sheathing; unmistakable by size

Compound umbel very large (10–30cm); outer florets have enlarged, asymmetric outer petals (enlargement similar in function to ray florets in Asteraceae — increasing display); petals white; ovary inferior; fruit broadly winged with conspicuous resin canals

Moist meadows, streambanks, forest edges; montane to subalpine; typically near streams

Oreoxis alpina

Apiaceae

Perennial herb from a taproot; low cushion-forming; strictly alpine; a characteristic small Apiaceae of CO tundra (Oreoxis = mountain smell)

Basal, pinnately to bipinnately compound; ultimate segments small and narrow; glabrous; forming a rosette

Compound umbel small and low; petals yellow (note: yellow is typical of alpine Apiaceae in CO); calyx teeth present; stamens 5; ovary inferior; fruit a schizocarp with narrow wings; involucre and involucel of narrow bracts

Alpine tundra, rocky fell-fields, exposed ridges; strictly alpine