CENTAUREA DILUTA

Family and Genus:- See- COMPOSITAE

Common Names:- North African Knapweed.

Homotypic synonyms:- Calcitrapa diluta; Hymenocentron dilutum.

Meaning:- Centaurea. From Greek kentauros, “centaur”, reflecting the traditional medicinal association of knapweeds with the centaur Chiron.
                  Diluta. Latin, “diluted” or “pale”, referring to the relatively pale coloration.

General description:- A perennial knapweed with branched stems and pink to purple capitula, occurring in Britain as an introduced casual or naturalised alien.

Stems:-
1) Usually 30-100 cm high, erect, branched, ridged and variably cobwebby to
    pubescent.

Leaves:-
1) Lower, alternate, petiolate, oblong to lanceolate, entire, toothed or pinnatifid.
2) Upper, alternate, sessile or shortly petiolate, narrower and usually less divided.

Flowers:-
1) Capitula, terminal, solitary, discoid and ovoid to subglobose.
2) Phyllaries, imbricate; appendages pale to brownish, scarious and fringed or
    toothed.
3) Receptacle, densely setose.
4) Florets, all tubular, pink to purple; marginal florets may be enlarged and sterile,
    central florets bisexual and fertile.
5) Stamens, 5 in fertile florets, with anthers united into a tube around the style.
6) Style, bifid at the apex.
7) Ovary, inferior, unilocular, with a single ovule.

Fruit:-
1) Cypsela, oblong to obovoid and compressed.
2) Pappus, present, of unequal bristles.

Distinguishing features:-
An introduced Centaurea requiring care in identification; the involucral phyllary appendages, leaf division and mature cypselas are useful diagnostic characters.

Flowering time:- July to September.

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Toxicity:- No significant toxicity is established; ingestion is not recommended without reliable evidence.

Habitat:- Waste ground, roadsides, dockland, railway land and other dry disturbed places, often associated with imported seed or former wool and grain traffic.

Distribution:- Introduced in Great Britain. Native to Macaronesia and the western Mediterranean region, including north-western Africa and Spain.

Conservation status:- Introduced in Great Britain; no native GB Red List category applies.

Photo by:- Photos by:- Popi Bormpoudaki