8. Tanacetum cinerariifolium (Trevir) Schultz-Bip., Tanacet. 58. 1844; Heywood in Tutin et al., Fl. Europ. 4: 171. 1976; Grierson in Dassan. & Fosberg, Rev. Handb. Fl. Ceylon 1: 238. 1980; Kitam. & S. Gould in Hara et al., Enum. Fl. Pl. Nepal 3: 45. 1985.
Pyrethrum cinerariifolium Trevir, Ind. Sem. Hor. Vratis. App. 2: 2. 1820; DC., Prodr. 6: 55. 1837; Tzvelev in Schischk. & Bobrov, Fl. USSR 26: 205. 2000 (Engl. transl.); Chrysanthemum cinerariifolium (Trevir.) Vis., Fl. Dalm. 22: 421. 1965; R. R. Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 731. 1972.
Perennial, with ± unbranched, up to 45 cm tall, erect, sparsely leafy, densely appressed silvery grayish pubescent stems from woody, suberect rhizome. Leaves on up to 15 cm long petioles, densely appressed silvery-gray hairy on both sides or glabrescent above, punctate glandular, laminas ovate or oblong, usually shorter than petioles, basal deeply 3-pinnatisect into linear-oblong, 0.75 – 2 mm broad, ± acute ultimate segments, upper leaves smaller, ± sessile, weakly dissected. Capitula radiate, usually solitary, terminal. Involucre campanulate, variable in diameter, phyllaries grayish pubescent, coriaceous to herbaceous, outer lanceolate, 3.5 – 5 mm long, ± acute, without scarious margins, inner phyllaries whitish, membranous on margins and dilated obtuse apices. Ray-florets 12-15, with 7 – 15 x 3 – 5 mm, ± crenately 3-lobed ligules. Disc-florets with 3 – 5 mm long, 5-lobed, yellow corolla tube. Cypselas oblong, 2.75 – 3.5 mm long, 5-ribbed, finely glandulose. Pappus coroniform, 0.5 – 1 mm long, finely toothed.
Fl. Per.: June-September.
Type: Described from Yugoslavia.
“Pyrethrum” is cultivated as a commercial crop in Kashmir for making pyrethrum powder (Stewart, l. c.) which is source of natural insecticides that are widely used in agriculture and for domestic purposes, the active constituents are recovered from the dried flower heads; Distribution: NE Italy, Yugoslavia, Albania, Greece, Caucasus, Central Asia; introduced and cultivated in Indo-Pakistan subcontinent, Sri Lanka, Malaya, China, Australia and USA.