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Vernonia gigantea

(Giant Ironweed)

Overview

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Interesting Facts

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Common Names

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Common Names in English:

Giant Ironweed, Tall Ironweed

Description

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Family Compositae

The largest family of flowering plants , the Compositae (Asteraceae), comprising about 1,100 genera and more than 20,000 species and characterized by many small flowers arranged in a head looking like a single flower and subtended by an involucre of bracts. A head may consist of both ray flowers and disk flowers, as in the sunflower, of disk flowers only, as in the burdock, or of ray flowers only, as in the dandelion.

Genus Vernonia

Perennials, 2-20(-30+) dm (rhizomatous or not) . Leaves usually mostly cauline (rarely mostly basal or basal and cauline) ; sessile or petiolate ; blades ovate , elliptic , lanceolate, oblanceolate , spatulate , linear , or filiform , bases usually ± cuneate (rounded-truncate in V. pulchella), margins usually toothed (rarely entire), apices acute to attenuate, abaxial faces usually ± scabrellous to strigillose or tomentose to pannose , sometimes glabrate or glabrous , usually resin-gland-dotted (sometimes ± pitted ), adaxial faces ± scabrellous or glabrate, sometimes resin-gland-dotted (rarely pitted) . Heads discoid , ± pedunculate , not subtended by foliaceous bracts, (6-) 40-100+ in ± corymbiform to paniculiform arrays (6-) 10-25+ cm diam. Involucres ± campanulate to obconic or hemispheric , 3-8(-11+) mm diam. Phyllaries 18-70+ in 4-7+ series, the outer ovate to lanceolate or subulate , inner ± lanceolate to oblong , all ± chartaceous , margins entire, often ciliolate , tips rounded (then sometimes apiculate ), or acuminate, subulate, or filiform, faces glabrous or sparsely strigillose to tomentose, sometimes ± gland-dotted. Florets 9-30(-65+) ; corollas usually purplish or pink (rarely white), tubes longer than funnelform throats , lobes 5, lance-linear , ± equal. Cypselae ± columnar , sometimes arcuate , 8-10-ribbed, glabrous or ± strigillose to hirtellous, often resin-gland-dotted; pappi persistent , of 20-30+ outer, erose to subulate scales or bristles plus 20-40+ inner, longer, subulate to setiform scales or bristles. x = 17.

Species 20 or so: mainly c, e North America, n Mexico, 2-3 species in South America.

The circumscription of Vernonia adopted here follows that of H. Robinson (1999) .

Vernonias hybridize ; almost every one of the species recognized here has been noted as sometimes hybridizing with one or more others. Putative hybrid plants are usually intermediate between parentals in some traits ; such plants may not "key" satisfactorily to any of the species treated here. Some putative hybrids have been named. Vernonia guadalupensis is "without much doubt a hybrid of V. baldwinii Torrey and V. lindheimeri Engelmann & Gray" (L. H. Shinners 1950) ; V. vulturina Shinners (known only from the type collection ) may be a product of V. baldwinii × V. marginata; V. ×georgiana Bartlett may refer to V. acaulis × V. angustifolia. Additional putative hybrids (S. B . Jones 1964) are V. ×concinna Gleason (V. ovalifolia × V. angustifolia), V. ×dissimilis Gleason (V. altissima × V. angustifolia), and V. ×recurva Gleason (V. pulchella × V. angustifolia) .[1]

Physical Description

Species Vernonia gigantea

Plants 8-20(-30+) dm. Stems puberulent , glabrescent . Leaves mostly cauline; blades ± lanceolate, 12-25+ cm × 20-60+ mm, l/w = (3.5-) 4-7+, abaxially scabrellous (hairs awl-shaped ), sometimes glabrescent, not or sparsely resin-gland-dotted, adaxially strigillose , glabrescent, not resin-gland-dotted. Heads in corymbiform-scorpioid arrays. Peduncles 1-12(-20+) mm. Involucres broadly campanulate to hemispheric , 4-5+ × 4-5 mm. Phyllaries 30-40+ in 4-5 series, glabrate , margins ciliolate , the outer lance-ovate, 1-2 mm, inner oblong , 3.5-5 mm, tips acute or rounded-apiculate. Florets (9-) 18-24(-30). Cypselae 2.5-3.5 mm; pappi usually purplish, sometimes stramineous , outer scales 20-25, 0.5-1 mm, contrasting with 35-40+, 4.5-6+ mm inner bristles . 2n = 34. [source]

Habit: Forb/herb

Flowers: Bloom Period: June, July, August, September. • Flower Color: blue-violet, lavender, magenta, purple, red-purple, violet

Size/Age/Growth

Size: 6-8' tall.

Habitat

Flood plains ; 10-300 m [2].

Typically found at an altitude of 0 to 1,092 meters (0 to 3,583 feet).[3]

Biology

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Reproduction

Duration: Perennial

Growth

Culture: Space 12-15" apart.

Soil: Minimum pH: 5.1 • Maximum pH: 7.5

Sunlight: Sun Exposure: Sun to Partial Shade.

Temperature: Cold Hardiness: 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a. (map)

Taxonomy

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Synonyms

Chrysocoma gigantea Walter • Vernonia altissima Nuttall • Vernonia altissima var. taeniotricha S. F. Blake • Vernonia gigantea ovalifolia (Torrey & A. Gray) Urbatsch • Vernonia ovalifolia Torrey & A. Gray

Notes

Name Status: Accepted Name .

Comment: Data Providers: IPNI, Tropicos, LCR Editor. GCC LSID: urn :lsid:compositae.org:names:6B52E358-FEDD-429A-AF97-9AA09B44E3C0

Last scrutiny: 31-Oct-09

Similar Species

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Members of the genus Vernonia

ZipcodeZoo has pages for 35 species, subspecies, varieties, forms, and cultivars in this genus:

V. acaulis (Stemless Ironweed) · V. albicaulis (Santa Maria) · V. angustifolia mohrii (Tall Ironweed) · V. anthelmintica (Ironweed) · V. arkansana (Arkansas Ironweed) · V. baldwinii (Baldwin Ironweed) · V. blodgettii (Blodgetts Ironweed) · V. borinquensis (Puerto Rico Ironweed) · V. concinna (Ironweed) · V. dissimilis (Ironweed) · V. fasciculata corymbosa (Ironweed) · V. flaccidifolia (Tennessee Ironweed) · V. galamensis (Ironweed) · V. galamensis galamensis (Ironweed) · V. georgiana (Ironweed) · V. gigantea (Giant Ironweed) · V. gigantea gigantea (Giant Ironweed) · V. gigantea ovalifolia (Giant Ironweed) · V. glauca (Broadleaf Ironweed) · V. guadalupensis (Guadalupe Ironweed) · V. illinoensis (Illinois Ironweed) · V. larsenii (Larsen's Ironweed) · V. lettermannii (Gray Narrowleaf Ironweed) · V. lindheimeri (Woolly Ironweed) · V. marginata (Ironplant) · V. missurica (Missouri Ironweed) · V. noveboracensis (New York Ironweed) · V. noveboracensis 'Richard Simon' (New York Ironweed) · V. peralta (Ironweed) · V. proctori (Proctor's Ironweed) · V. pulchella (Georgia Ironweed) · V. sericea (Longshoot) · V. texana (Texas Ironweed) · V. vulturina (Ironweed) · V. x georgiana (Ironweed)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal February 01, 2008:

Identifiers

Footnotes

  1. John L. Strother "Vernonia". in Flora of North America Vol. 19, 20 and 21 Page 58, 67, 200, 201, 206, 207. Oxford University Press. Online at EFloras.org. [back]
  2. "Vernonia gigantea". in Flora of North America Vol. 19, 20 and 21 Page 208, 212. Oxford University Press. Online at EFloras.org. [back]
  3. Mean = 199.240 meters (653.675 feet), Standard Deviation = 150.350 based on 804 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/15/2012