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Centaurea sulphurea

(Sicilian Starthistle)

Overview

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Interesting Facts

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Common Names

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Common Names in English:

Sicilian Starthistle, Sicilian Star Thistle, Sicilian Star-Thistle, Sicilian Thistle, Sulphur Knapweed, Sulphur Knapweed Centaurea Sulphurea, Sulphur Starthistle, Sulphur-Colored Sicilian thistle

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 Centaurea

Annuals , biennials, or perennials, 20-300 cm, glabrous or tomentose . Stems erect , ascending , or spreading , simple or branched. Leaves basal and cauline; petiolate or sessile; proximal blade margins often ± deeply lobed , (spiny in C. benedicta ), distal ± smaller, often entire, faces glabrous or ± tomentose, sometimes also villous , strigose , or puberulent , often glandular-punctate. Heads discoid , disciform , or radiant, borne singly or in corymbiform arrays. Involucres cylindric or ovoid to hemispheric . Phyllaries many in 6-many series, unequal, proximal part appressed , body margins entire. distal parts expanded into erect to spreading, usually ± dentate or fringed , linear to ovate appendages , spine. tipped or spineless. Receptacles flat, epaleate, bristly . Florets 10-many; outer usually sterile , corollas slender and inconspicuous to much expanded, ± bilateral ; inner fertile , corollas white to blue, pink, purple, or yellow, bilateral or radial , often bent at junction of tubes and throats , lobes linear-oblong, acute; anther bases tailed , apical appendages oblong ; style branches: fused portions with minutely hairy nodes, distinct portions minute. Cypselae ± barrel-shaped, ± compressed , smooth or ribbed , apices entire (denticulate in C. benedicta ), glabrous or with fine, 1-celled hairs , attachment scar . lateral (with or without elaiosomes) ; pappi 0 or ± persistent , of 1-3 series of smooth or minutely barbed , stiff bristles or narrow scales . x = 8, 9, 10, 11, 12, 13, 15.

Species ca. 500: introduced ; Eurasia , n Africa, widely introduced worldwide.

Taxonomic limits of Centaurea have been controversial. The genus has great morphologic diversity , and studies have revealed much cytologic (e.g. , N. Garcia-Jacas et al. 1996) and palynologic (e.g., G. Wagenitz 1955) variation as well. During the nineteenth and twentieth centuries, various taxonomists attempted, with limited success, to divide Centaurea into smaller genera or workable infrageneric taxa. The relations of several satellite genera have been controversial as well.

Recent molecular phylogenetic studies (A. Susanna et al. 1995; N. Garcia-Jacas et al. 2000, 2001) have begun to clarify relationships within Centaurea and between Centaurea and other genera. These studies make it clear that Centaurea as traditionally defined is polyphyletic, and that generic boundaries should be realigned if monophyletic taxa are to be recognized. Some taxa traditionally included within Centaurea (e.g., the two native North American species, Centaurea americana and C. rothrockii) fall outside the redefined generic boundaries and are here treated in Plectocephalus. Others usually placed into segregate genera (e.g., Cnicus benedictus) are firmly nested within Centaurea. Because the type species of Centaurea (C. centaurium Linnaeus, an African species) falls outside the main lineage of the genus, a proposal has been made to conserve Centaurea with a different type species (W. Greuter et al. 2001), thereby maintaining the nomenclatural stability of most of the numerous species that do fall within the principal Centaurea clade.

Although several Centaurea species are widely established as members of the North American flora , and some of these are widely distributed invasive weeds , some of the taxa listed by J. T. Kartesz and C. A. Meacham (1999) are apparently waifs and not permanent members of the flora. These taxa are discussed informally immediately below.

Although Cnicus has usually been recognized as a distinctive monotypic genus, it has been merged into Centaurea by various authors (e.g., K . Bremer 1994; G. Wagenitz and F. H. Hellwig 1996) . Recent molecular systematic studies (N. Garcia-Jacas et al. 2000) provide additional evidence that it is nested within Centaurea.[1]

Physical Description

Species Centaurea sulphurea

Annuals, 10-100 cm. Stems simple to openly branched, branches ascending , villous to hispid with septate hairs and loosely tomentose . Leaves ± villous to hispid with septate hairs, minutely resin-gland- dotted ; basal winged-petiolate. blades oblong to oblanceolate , 10-15 cm, margins pinnately lobed , lobes acute, finely dentate ; cauline sessile, long-decurrent with narrow wings , linear-oblong to oblanceolate, 1-6 cm, entire or distally serrate with short, spine-tipped teeth. Heads disciform , borne singly or in open, few-headed corymbiform arrays, long-pedunculate. Involucres ovoid , 12-30 mm, distally constricted. Principal phyllaries: bodies greenish or stramineous , ovate to elliptic , glabrous , appendages spreading to reflexed , brown to blackish purple, each with palmately radiating cluster of spines, central spine stout, 1-2.5 cm, base dark brown to black, distally stramineous. Inner phyllaries: appendages acute or spine-tipped. Florets many; corollas yellow, all ± equal, 25-35 mm; corollas of sterile florets slender, inconspicuous. Cypselae dark brown, 5-8 mm, glabrous; pappi of many, brown to blackish, unequal bristles 6-7 mm. 2n = 24. [source]

According to R. Angelo (pers. comm. ), "The Kartesz citation is puzzling. This taxon [C. bovina] is not cited in the 1924 volume of Rhodora or anywhere in the first 50 years of Rhodora according to the index for that volume and our 50 year index (which is quite comprehensive). Also, there are no specimens identified as this taxon in the New England Botanical Club (NEBC) herbarium or from Massachusetts in the Harvard University Herbaria collections . We also looked for re-identifications in the other taxa in Centaurea in the NEBC and found no specimens that were earlier identified as C. bovina. The Vascular Plants of Massachusetts[...] (1999) of [B . A.] Sorrie and [P.] Somers does not list this taxon, nor does the Flora of the Northeast[...] (1999) by [D. W.] Magee and [H. E.] Ahles." [source]

Habit: Forb/herb

Flowers: Bloom Period: April, May, June. • Flower Color: pale yellow

Size/Age/Growth

Size: 24-36" tall.

Habitat

Disturbed sites, grasslands, woodlands, pastures, roadsides; 0-300 m [2].

Typically found at an altitude of 0 to 1,041 meters (0 to 3,415 feet).[3]

Biology

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Reproduction

Duration: Annual

Growth

Soil: Minimum pH: 6.1 • Maximum pH: 7.8

Sunlight: Sun Exposure: Full Sun .

Moisture: Drought Tolerance: High

Temperature: Cold Hardiness: Not Applicable (map)

Taxonomy

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Notes

Name Status: Accepted Name .

Comment: Data Providers: African Flowering Plants Database , New Zealand Plant Name Database, Govaerts World Compositae Checklist A-G, IPNI, Tropicos, Euro+Med. GCC LSID: urn :lsid:compositae.org:names:2B301E47-B3FF-426D-A809-C2A94B42136E

Last scrutiny: 20-Aug-09

Similar Species

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Members of the genus Centaurea

ZipcodeZoo has pages for 82 species, subspecies, varieties, forms, and cultivars in this genus:

C. akamantis (Akamas Centaury) · C. alpestris (Greater Centaury) · C. americana (American Basketflower) · C. americana 'Aloha' (American Knapweed) · C. americana 'Jolly Joker' (American Knapweed) · C. aspera (Rough Star-Thistle) · C. atropurpurea (Centaurea) · C. bella (Knapweed) · C. benoistii (Maroon Cornflower) · C. biebersteinii (Ballast Waif Centaurea Biebersteinii) · C. bovina (Pasture Knapweed) · C. cachinalensis (Flor Del Minero) · C. calcitrapa (Big-Head Purple Starthistle) · C. calcitrapoides (Smallhead Star-Thistle) · C. cineraria (Dusty Miller) · C. cineraria 'Colchester White' (Dusty Miller) · C. crupina (Crupina) · C. cyanoides 'Blue Carpet' (Cornflower) · C. cyanus (Bachelor's Button) · C. cyanus nana 'Jubilee Gem' (Bachelors Button) · C. cyanus 'Black Ball' (Bachelors Button) · C. cyanus 'Black Boy' (Bachelors Button) · C. cyanus 'Black Gem' (Bachelors Button) · C. cyanus 'Black Magic' (Bachelors Button) · C. cyanus 'Blue Boy' (Bachelors Button) · C. cyanus 'Blue Diadem' (Bachelors Button) · C. cyanus 'Classic Blue' (Bachelors Button) · C. cyanus 'Dwarf Blue Midget' (Bachelors Button) · C. cyanus 'Frosted Queen Mix' (Bachelors Button) · C. cyanus 'Frosty Mix' (Bachelors Button) · C. cyanus 'Mauve Queen' (Bachelors Button) · C. cyanus 'Polka Dot Mix' (Bachelors Button) · C. dealbata (Knapweed Centaurea Dealbata) · C. dealbata 'Rosea' (Knapweed) · C. debeauxii (Meadow Knapweed) · C. debeauxii thuillieri (Meadow Knapweed) · C. debeauxii subsp. thuillieri (Meadow Knapweed) · C. depressa (Centaurea) · C. diffusa (Diffuse Knapweed) · C. diluta (North African Knapweed) · C. eriophora (Sand-Heath) · C. gymnocarpa (Velvet Centaurea) · C. hypoleuca DC. 'John Coutts' (Knapweed) · C. iberica (Iberian Knapweed) · C. jacea (Brown Knapweed) · C. jacea x nigra (Hybrid Knapweed Centaurea Jacea X Nigra) · C. macrocephala (Armenian Basketflower) · C. melitensis (Cockspur Thistle) · C. moncktonii (Meadow Knapweed) · C. montana (Mountain Bluet) · C. montana 'Alba' (Mountain Bluet) · C. montana 'Amethyst in Snow' (Mountain Bluet) · C. montana 'Dot Purple' (Mountain Bluet) · C. montana 'Gold Bullion' (Batchelor's Button) · C. moschata 'Dairy Maid' (Sweet Sultan) · C. moschata 'Imperialis' (Sweet Sultan) · C. moschata 'The Bride' (Sweet Sultan) · C. nigra (Black Knapweed) · C. nigrescens (Short-Fringe Starthistle) · C. orientalis (Centaurea) · C. ovina (Lilac Knapweed) · C. paniculata (Jersey Knapweed) · C. phrygia (Scandinavian Starthistle) · C. pindicola (Centaurea) · C. pulcherrima (Pink Bachelors Button) · C. 'Pulchra Major' (Bachelor's Button) · C. ragusina (Dubrovacka Zecina) · C. rothrockii (Basket Flower) · C. scabiosa (Great Starthistle) · C. solstitialis (Barnaby Star-Thistle) · C. solstitialis solstitialis (St. Barnaby's Thistle) · C. stoebe (Spotted Knapweed) · C. sulphurea (Sicilian Starthistle) · C. thuillieri (Meadow Knapweed) · C. transalpina (Alpine Knapweed) · C. trichocephala (Feather-Head Knapweed) · C. triumfetti (Squarrose Knapweed Centaurea Triumfetti) · C. triumfettii (Spreading Thistle) · C. uniflora (Single-Flower Knapweed) · C. uniflora nervosa (Singleflower Knapweed) · C. xpratensis (Meadow Knapweed) · C.'Nigra' (Bachelor Buttons)

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 November 18, 2007:

Identifiers

Footnotes

  1. David J. Keil, Jörg Ochsmann "Centaurea". in Flora of North America Vol. 19, 20 and 21 Page 52, 57, 58, 67, 83, 84, 96, 171, 172, 176, 177, EFloras.org. [back]
  2. "Centaurea sulphurea". in Flora of North America Vol. 19, 20 and 21 Page 182, 183, 194. Oxford University Press. Online at EFloras.org. [back]
  3. Mean = 673.390 meters (2,209.285 feet), Standard Deviation = 343.630 based on 18 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
Last Revised: 7/15/2012