Arnebia guttata Bunge

The species is variable throughout its distributional range. that Popov (l.c. 176) employs in differentating between A. guttata, A. tibetana and A. thomsonii are not satisfactory. Hooker (l.c.) also rather vaguely distinguishes A. tibetana from A. thomsonii, on the bases of the nutlet being to smooth. Kazmi (l.c. 495) distinguishes the two taxa on characters that largely overlap. In the present treatment I include A. tibetana and A. thomsonii as synonyms of A. guttata. Popov (l.c.) and Kazmi (l.c.) mention purple spots on the corolla of A. guttata which I have failed to observe.

There are biennial and perennial groups within the species, the former predominantly in Russia and Mongolia, the latter in Xizang and Xinjiang (Arnebia tibetana). These groups, which lack the blackish purple spots on corolla lobes, probably represent distinct subspecies.

The roots are used medicinally.

Perennial or annual, erect to procumbent herb. Roots slender or up to 20 mm long, branched, excluding a dark purple dye. Stem branched, sometimes simple, up to 30 cm long; densely hairy with stiff white hairs (up to 2.5 mm long) with bulbous base, intermixed with soft weaker hairs. Leaves greyish or greyish-green in colour, densely hairy; basal leaves 40-70 x 4-8 mm, cauline smaller, oblanceolate, obtuse. Inflorescence a terminal cyme up to 17 cm long (in fruit). Flowers secund, heterostylic, orange or yellow, bracteate; bracts 6-8 x 1.2 mm, lanceolate, obtuse. Calyx 5-partite, densely hairy, 6-7 mm long, up to 11 mm in fruit; lobes linear. Corolla. hairy to the outside; tube 8 mm (in short styled flowers) to 11 mm long (in long styled flowers); limb 5-6 mm broad, spreading; lobes obtuse. Anthers 1.7 mm long, attached in the middle of corolla tube or at the throat and subexserted. Style forked, subexserted (in long styled flowers) or not. Stigmas 2, compressed. Nutlets 2-3 mm long, dull grey to yellowish brown, ovoid, with a broad base, tuberculate-the tubercles dense or not.

Herbs perennial or sometimes biennial. Roots containing purple dye. Stems usually 2-4, sometimes only 1, erect, much branched, 10-25 cm tall, densely spreading long hispid, short strigose. Leaves sessile, spatulate-linear to linear, 1.5-5.5 cm × 3-11 mm, densely hirsute, hairs discoid at base, apex obtuse. Inflorescences crowded; cymes 3-10 cm; bracts linear-lanceolate. Flowers heterostylous. Calyx lobes linear, 6-10 mm, to 1.5 cm in fruit, long hispid. Corolla yellow, tubular-campanulate, pubescent outside; limb 7-12 mm wide; lobes spreading, broadly ovate or semiorbicular, frequently purple spotted. Anthers oblong, ca. 1.8 mm. Style filiform, apex 2-lobed; stigma reniform. Nutlets light yellow-brown, triangular-ovate, 2.5-3 mm, tuberculate. Fl. and fr. Jun-Oct.

Distribution: Afghanistan, Pakistan.

Fl. Per.: May-August.

Gobi Desert, rocky slopes, gravelly marshes. W Gansu, N Hebei, Nei Mongol, Ningxia, Xinjiang, Xizang [Afghanistan, NW India, Kazakhstan, Kyrgyzstan, Mongolia, Pakistan, Russia, Tajikistan, Turkmenistan, Uzbekistan]

Arnebia thomsonii C. B. Clarke; A. tibetana Kurz; Lithospermum guttatum (Bunge) I. M. Johnston; Macrotomia guttata (Bunge) Farrer.