Isatis tinctoria
L., Sp. Pl. 670. 1753; Hook. f. & T. Anderson in Fl. Brit. India 1:
163. 1872.
Eng.: Dyer's wood.
Herbs, biennial or rarely perennial, erect, much-branched, glabrous or hirsute, subglaucous, up to 1 m high. Basal leaves rosulate, oblong-lanceolate or oblanceolate, shortly stalked, entire or weakly dentate, 5 - 15 x 1 - 3 cm; cauline leaves gradually smaller, linear or linear-lanceolate, acutely auricled and amplexicaul at base, entire. Inflorescence a loose panicle elongating up to 12 cm long in fruit; pedicels filiform, 5 - 8 mm long in fruit, more or less deflexed. Sepals 2 - 2.5 mm long, glabrous. Petals oblong-obovate, cuneate towards base, yellow, 3 - 5 mm long. Fruit oblong, elliptic-obovate, cuneate towards base, obtuse or emarginate at apex, 10 - 25 x 2 - 5 (-9) mm, glabrous or puberulent; wings thick, midrib usually slender. Seeds oblong to ellipsoid, brown, 3 - 4 x 1 mm.
Fl. & Fr. May - June.
Distrib. India: Jammu & Kashmir and Himachal Pradesh.
Cultivated in Europe, N. and E. Asia.
Notes. The blue and green pigments extracted from the leaves are used as dye in textile industry.
A highly polymorphic species.
Herbs, biennial or rarely perennial, erect, much-branched, glabrous or hirsute, subglaucous, up to 1 m high. Basal leaves rosulate, oblong-lanceolate or oblanceolate, shortly stalked, entire or weakly dentate, 5 - 15 x 1 - 3 cm; cauline leaves gradually smaller, linear or linear-lanceolate, acutely auricled and amplexicaul at base, entire. Inflorescence a loose panicle elongating up to 12 cm long in fruit; pedicels filiform, 5 - 8 mm long in fruit, more or less deflexed. Sepals 2 - 2.5 mm long, glabrous. Petals oblong-obovate, cuneate towards base, yellow, 3 - 5 mm long. Fruit oblong, elliptic-obovate, cuneate towards base, obtuse or emarginate at apex, 10 - 25 x 2 - 5 (-9) mm, glabrous or puberulent; wings thick, midrib usually slender. Seeds oblong to ellipsoid, brown, 3 - 4 x 1 mm.
Fl. & Fr. May - June.
Distrib. India: Jammu & Kashmir and Himachal Pradesh.
Cultivated in Europe, N. and E. Asia.
Notes. The blue and green pigments extracted from the leaves are used as dye in textile industry.
A highly polymorphic species.
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