CENTAUREA L. - KNAPWEED
Scientific Description:
Annual, biennial or perennial herbs, rarely small shrubs with spiny branches or larger subshrubs with evergreen leaves; often tomentose or scabrous to hirsute with multicellular hairs, rarely glabrous, sessile glands very frequent. Leaves alternate, sometimes all radical, very variable, but (in Turkey) never spiny (except spinulose in Centaurea odyssei Wagenitz) often pinnatifid, sometimes decurrent. Capitula heterogamous, disciform or radiant. Involucre ovoid, sub-globose, hemispherical, nearly cylindrical, oblong or fusiform; phyllaries pluriseriate, imbricate, ± rigid, nearly always with a scarious, straw-textured or coriaceous appendage of very variable form: entire or fringed to ciliate, orbicular, lanceolate or triangular, blunt or ending in a mucro, spinule or rigid spine, sometimes appendage consisting of a mere mucro or spinule or rarely altogether absent. Receptacle with smooth bristles. Flowers pink, purple (to blackish-purple), blue, yellow or whitish; marginal ones neuter (sometimes with staminodes), funnel-shaped with 5−8 or more segments or nearly filiform and very inconspicuous with 4−5 linear segments, central ones hermaphrodite. Achenes usually glabrous when ripe, ± laterally compressed, apex rounded or truncate, hilum lateral near base, often with elaiosome. Pappus of several series of unequal scabrous, barbellate or plumose bristles, gradually elongated towards centre, but innermost row often short and more scale-like, pappus persistent or rarely caducous, sometimes absent.
Reference:
Wagenitz G (1975). Centaurea L., In: Davis PH (ed.), Flora of Turkey and the East Aegean Islands, Edinburgh University Press, Edinburgh, 5: 465.
Public Description:
Centaurea is a genus of annual, biennial or perennial herbs, known as “centaury”, “centory”, “starthistles”, “knapweeds” or “centaureas”, is native to the Old World (Africa, Europe and Asia) and chiefly centred in the Mediterranean region and the Middle East. There are approximately 734 species in the world and 157 species (192 taxa) in Türkiye. The flowers are pink, purple, blue, yellow or whitish colors. The knapweeds produce abundant amounts of nectar, especially in the calcareous soil, and this high amount of nectar makes them attractive to insects and larvae. This leads some species to be highly invasive.
References:
Anonymous 1 (2016). https://en.wikipedia.org/wiki/Centaurea, Accessed date: 06.01.2016.
Anonymous 2 (2016). http://www.theplantlist.org/1.1/browse/A/Compositae/Centaurea//, Accessed date: 06.01.2016.
Anonymous 3 (2018). https://www.britannica.com/plant/Centaurea, Accessed date: 03.03.2018.
Uysal T (2012). Centaurea. L., In: Güner, A., Aslan, S., Ekim, T., Vural, M. & Babaç, M.T. (eds.), Türkiye Bitkileri Listesi (Damarlı Bitkiler). Nezahat Gökyiğit Botanik Bahçesi ve Flora Araştırmaları Derneği Yayını. İstanbul, pp. 127–140.
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