The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Bachelor's button, centaurée des montagnes, montane starthistle, mountain bluet, mountain bluet knapweed, mountain cornflower, mountain cornflower or bluet, mountain knapweed, perennial cornflower

croix de malte, Maltese knapweed, Maltese star thistle or centaury, Maltese star-thistle, Napa thistle, tocalote

Habit Perennials, 25–80 cm, from rhizomes or stolons. Annuals, 10–100 cm, herbage loosely gray-tomentose and villous with jointed multicellular hairs, sometimes minutely scabrous, minutely resin-gland-dotted.
Stems

1–several, erect, simple or sparingly branched, villous with septate hairs and thinly arachnoid-tomentose with long, simple hairs.

1–few, few–many branched distally.

Leaves

thinly villous and ± tomentose, glabrate;

proximal leaves winged-petiolate, blades 10–30 cm, margins entire or remotely dentate to pinnately lobed;

mid and distal leaves sessile, blades decurrent, ovate to oblong or lanceolate, entire or remotely denticulate.

basal and proximal cauline petiolate or tapering to base, usually absent at anthesis, blades oblong to oblanceolate, 2–15 cm, margins entire to dentate or pinnately lobed;

cauline long-decurrent, blades linear to oblong or oblanceolate, 1–5 cm, entire or dentate.

Involucres

ovoid to ± campanulate, 20–25 mm.

ovoid, 10–15 mm, loosely cobwebby-tomentose or becoming glabrous.

Florets

35–60+;

sterile florets 10–20, corollas blue (white, purple, or pink), 2.5–4.5 cm, corolla tube elongate.

many;

corollas yellow, those of sterile florets 10–12 mm, slender, inconspicuous, those of fertile florets 10–12 mm.

Disc florets

25–40+;

corollas purple, ca. 20 mm;

anthers dark blue-purple.

Inner phyllaries

appendages entire, acute or spine-tipped.

Heads

radiant, borne singly or in few-headed corymbiform arrays; (peduncles to 7 cm).

disciform, 1–few at branch tips, borne singly or in open leafy corymbiform arrays, sometimes clustered in distal axils, sessile or pedunculate.

Cypselae

± brown, 5–6 mm, sericeous;

pappi of bristles 0.5–1.5 mm.

dull white or light brown, ca. 2.5 mm, finely hairy;

pappi of many white, unequal, stiff bristles 2.5–3 mm.

Principal

phyllaries: bodies greenish, ovate to lanceolate, scarious-margined, appendages appressed, brown to black, unarmed, decurrent on phyllary margins, pectinate-fringed, puberulent;

innermost phyllaries sometimes unappendaged.

phyllaries: bodies ± stramineous, ovate, appendages purplish, spiny-fringed at base, each tipped by slender spine 5–10 mm.

2n

= 24 (Germany), 40 (Russia), 44 (France).

= 24.

Centaurea montana

Centaurea melitensis

Phenology Flowering summer (Jun–Aug). Flowering mostly spring–summer (Apr–Jul).
Habitat Escaped from cultivation, roadsides, woodlands, sagebrush scrub Roadsides, fields, pine-oak woodlands, chaparral, agricultural areas
Elevation 0–1400 m (0–4600 ft) 0–1500 m (0–4900 ft)
Distribution
from FNA
AK; ID; ME; MI; MN; MT; NH; NY; OR; PA; UT; WA; WI; BC; NB; NF; ON; QC; SPM; Europe [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AZ; CA; GA; ID; IL; MA; MO; MS; NJ; NM; NV; OR; PA; TX; UT; WA; WI; BC; Mexico (Baja California); Europe; Asia; Africa [Widely introduced]
[WildflowerSearch map]
[BONAP county map]
Discussion

Centaurea montana is a very handsome plant, native to the mountains of Europe, now widely cultivated as an ornamental.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Centaurea melitensis is native to the Mediterranean region. It is listed as a noxious weed in New Mexico.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 19, p. 185. FNA vol. 19, p. 193.
Parent taxa Asteraceae > tribe Cardueae > Centaurea Asteraceae > tribe Cardueae > Centaurea
Sibling taxa
C. benedicta, C. calcitrapa, C. cyanus, C. depressa, C. diffusa, C. diluta, C. iberica, C. jacea, C. macrocephala, C. melitensis, C. nigra, C. nigrescens, C. phrygia, C. scabiosa, C. solstitialis, C. stoebe, C. sulphurea, C. virgata, C. ×moncktonii
C. benedicta, C. calcitrapa, C. cyanus, C. depressa, C. diffusa, C. diluta, C. iberica, C. jacea, C. macrocephala, C. montana, C. nigra, C. nigrescens, C. phrygia, C. scabiosa, C. solstitialis, C. stoebe, C. sulphurea, C. virgata, C. ×moncktonii
Name authority Linnaeus: Sp. Pl. 2: 911. (1753) Linnaeus: Sp. Pl. 2: 917. (1753)
Web links