Rudbeckia hirta L.

Blackeyed susan (en), Rudbeckie hérissée (fr), Rudbeckia hérissé (fr)

Species

Angiosperms > Asterales > Asteraceae > Rudbeckia

Characteristics

Biennial or short-lived perennial 3–10 dm, ± hispid or hirsute throughout; lvs variable, the lower mostly oblanceolate to elliptic and long-petiolate, the others lance-linear to oblong or ovate, mostly sessile; heads mostly long-pedunculate, the hemispheric or ovoid disk 12–20 mm wide, dark purple or brown (yellow); invol bracts copiously hirsute or hispid, sometimes much elongate; rays 8–21, orange or orange-yellow, sometimes darker or marked with purple at base, 2–4 cm; receptacular bracts acute, ± hispid or hispidulous near the tip; style-appendages elongate, subulate; pappus none; 2n=38. Various habitats; Nf. to Fla., w. to B.C. and Mex. June–Oct. Var. hirta occurs mostly in relatively undisturbed habitats in the mts. from Pa. to Ga. and Ala., and sparingly n. to Me. and w. to Ill.; it has coarsely toothed lvs, the basal ones with the blade 2.5–7 cm wide and about twice as long, the cauline ones lance-ovate to ovate or pandurate. Var. pulcherrima Farw. (R. serotina) is widespread especially in disturbed habitats; it has entire or finely toothed lvs, the basal ones with lanceolate or oblanceolate blade 1–2.5(–5) cm wide and (3–)4–5 times as long, the cauline ones spatulate or oblanceolate to broadly linear.
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Annuals, biennials, or perennials, to 100 cm (taprooted or roots fibrous). Stems hispid to hirsute (hairs spreading, 1+ mm). Leaves: blades elliptic, lanceolate, or ovate (not lobed), bases attenuate to cuneate, margins entire or serrate, apices acute, faces hispid to hirsute; basal petiolate, blades 8–30 × 0.5–7 cm; cauline petiolate or sessile, blades (sometimes pandurate) 3–20 × 0.4–4 cm. Heads borne singly or (2–5) in loose, corymbiform arrays. Phyllaries to 3 cm (faces hispid to hirsute). Receptacles hemispheric to ovoid; paleae 4–6 mm, apices acute, often attenuate, abaxial tips hirsute to hispid. Ray florets 8–16; laminae (usually uniformly yellow to yellow-orange or with a basal maroon splotch, sometimes mostly maroon) elliptic to oblong or oblanceolate, 15–45 × 5–10 mm, abaxially hispid to hirsute. Discs 12–22 × 10–20 mm. Disc florets 250–500+; corollas proximally yellowish green, distally brown-purple, 3–4.2 mm; style branches ca. 1.5 mm, apices subulate. Cypselae 1.5–2.7 mm; pappi 0.
Annuals, biennials, or perennials. Stems hispid to hirsute. Leaf blade elliptic, lanceolate, or ovate, hispid to hirsute, base attenuate to cuneate, margin entire or serrate, apex acute; basal leaves petiolate, blade 8-30 × 0.5-7 cm; cauline leaves petiolate or sessile, blade 3-20 × 0.4-4 cm. Capitula solitary or 2-5 in loose, corymbiform arrays; phyllaries to 3 cm; receptacle hemispheric to ovoid; paleae 4-6 mm, abaxially hirsute to hispid at apex, apex acute, often attenuate. Ray florets 8-16; corolla limb usually uniformly yellow to yellow-orange or with a basal maroon splotch, sometimes mostly maroon, elliptic to oblong or oblanceolate, 15-45 × 5-10 mm, abaxially hispid to hirsute. Disk 1.2-2.2 × 1-2 cm; disk florets numerous; corolla proximally yellowish green, distally brown-purple, 3-4.2 mm; style branches ca. 1.5 mm, apex subulate. Achenes 1.5-2.7 mm; pappus absent. Fl. Jun-Sep.
A herb. It can grow for one or more years. The leaves are entire. The lower leaves are oval and 8-30 cm long by 1-7 cm wide and the upper leaves are smaller. The ray flowers are yellow to orange and these are round dark purplish-brown disc flowers.
Life form
Growth form herb
Growth support free-standing
Foliage retention deciduous
Sexuality hermaphrodite
Pollination entomogamy
Spread anemochory
Mature width (meter) 1.0
Mature height (meter) 1.5 - 1.8
Root system fibrous-root rhizome tap-root
Rooting depth (meter) 0.2
Root diameter (meter) 0.3
Flower color
Blooming months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Fruit color -
Fruiting months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Nitrogen fixer -
Photosynthetic pathway c3

Environment

Disturbed soils in Texas. Open woodlands, fields and roadsides at elevations of 30-300 metres.
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It is a temperate plant.
Light 4-8
Soil humidity 3-6
Soil texture 1-5
Soil acidity 4-7
Soil nutriment -
Hardiness (USDA) 4-8

Usage

Uses dye environmental use medicinal poison
Edible shoots
Therapeutic use Dermatological Aid (root), Ear Medicine (root), Anthelmintic (root), Pediatric Aid (root), Cold Remedy (root), Anthelmintics (root), Common cold (root), Earache (root), Edema (root), Menstruation disturbances (root), Snake bites (root), Wounds and injuries (root), Anthelmintic (unspecified), Gynecological Aid (unspecified), Kidney Aid (unspecified), Snake Bite Remedy (unspecified), Venereal Aid (unspecified), Pediatric Aid (unspecified), Heart Medicine (unspecified), Eye Medicine (unspecified), Poison (unspecified), Anti-inflammatory agents (unspecified), Antioxidants (unspecified), Hepatitis b (unspecified), HIV infections (unspecified)
Human toxicity -
Animal toxicity -

Cultivation

Can be grown by seedlings. Seeds needs stratification.
Mode seedlings
Germination duration (days) 7 - 21
Germination temperacture (C°) 21
Germination luminosity light
Germination treatment stratification
Minimum temperature (C°) -35
Optimum temperature (C°) -
Size -
Vigor -
Productivity -

Images

Habit

Rudbeckia hirta habit picture by Christine Berni (cc-by-sa)
Rudbeckia hirta habit picture by Shien Anna (cc-by-sa)
Rudbeckia hirta habit picture by Adrian (cc-by-sa)

Leaf

Rudbeckia hirta leaf picture by no bru (cc-by-sa)
Rudbeckia hirta leaf picture by Ga Coh (cc-by-sa)
Rudbeckia hirta leaf picture by Dylan Stills (cc-by-sa)

Flower

Rudbeckia hirta flower picture by Faircloth Tom (cc-by-sa)
Rudbeckia hirta flower picture by Tomáš Kortán (cc-by-sa)
Rudbeckia hirta flower picture by calderwook (cc-by-sa)

Distribution

Rudbeckia hirta world distribution map, present in Austria, Belgium, Bangladesh, Belarus, Switzerland, China, Cuba, Germany, Spain, France, United Kingdom of Great Britain and Northern Ireland, Croatia, Hungary, Italy, Kazakhstan, Kyrgyzstan, Liechtenstein, Moldova (Republic of), Myanmar, Netherlands, Norway, Poland, Romania, Russian Federation, Slovakia, Slovenia, Turkmenistan, Ukraine, United States of America, and Uzbekistan

Identifiers

LSID urn:lsid:ipni.org:names:223740-2
WFO ID wfo-0000027627
COL ID 4TMB7
BDTFX ID 58564
INPN ID 119406
Wikipedia (EN) Link
Wikipedia (FR) Link

Synonyms

Centrocarpha gracilis Rudbeckia gracilis Rudbeckia discolor Helianthus hirtus Rudbeckia brittonii Rudbeckia strigosa Rudbeckia monticola Centrocarpha hirta Rudbeckia amplectens Centrocarpha gracilis Centrocarpha hirta Rudbeckia hirta var. monticola Rudbeckia hirta var. hirta Rudbeckia hirta var. brittonii Rudbeckia hirta f. hirta Rudbeckia hirta

Lower taxons

Rudbeckia hirta var. angustifolia Rudbeckia hirta var. pulcherrima Rudbeckia hirta var. floridana