Isatis tinctoria, L.

7. I. tinctoria L. , Sp. Pl. 670 (1753)

(inch I. canescens DC. , I. litoralis Steven , I. taurica Bieb. ).

Biennial 50-120 cm. Cauline leaves with acute auricles. Petals 2-5-4 mm. Silicula 11-27 x 3- 7(-10) mm, usually oblong-obovate or elliptic-obovate, (2 |-)3- 5 times as long as wide, glabrous to tomentose; central rib usually slender. 2/z = 28. Most of Europe but rare in the north; cultivated since ancient times as a source of dye and probably introduced in many parts. All except Az BI Cr Fa Hb Is Sb.

As defined here this species is very variable, particularly in fruit shape and indumentum. Some of the more distinct component taxa are:

I. canescens DC. in Lam. & DC., Fl. Fr. ed. 3, 5: 598 (1815). Silicula 18-25x 4-7 mm, densely tomentose. Frequent in S. Europe.

I. tomentella Boiss. & Balansa in Boiss., Diagn. Pl. Or. Nov. 3 (5): 46 (1856) (/. canescens auct. ross., et auct. balcan. pro parte). Silicula 11-20 x 3-5-5 mm, elliptic-oblong, with cuneate base, pubescent. S. part of Balkan peninsula; Krym.

I. littoralis Steven ex DC. Reg. Veg. Syst. Nat. 2: 568 (1821) Silicula 15-27 x 5-10 mm, emarginate and with a prominent central rib. Krym.