Orobanche alba Steph. ex Willd.

Foodplant / parasite
underground tuber of Orobanche alba parasitises root of Thymus
Other: major host/prey

Foodplant / parasite
underground tuber of Orobanche alba parasitises root of Lamiaceae
Remarks: Other: uncertain
Other: minor host/prey

A very variable and widely distributed species. Some forms of Orobanche cernua Loefl., especially the var. pseudo-clarkei Jafri, may be confused with this species because of entire calyx segments in the lower flowers, but the corolla. shape and colour differs, and stamens inserted at c. the middle of corolla-tube. The species needs careful study with adequate material for recognizing infra-specific categories. Shortly 2-fid calyx segments have been noticed in some gatherings with the normal entire segments and Orobanche consimilis Schi.-Czeika only represents this form.

Annual or biennial, 15-30 (-45) cm tall, glandular-pubescent, slender, brownish in appearance, very variable in size. Scales usually 15-20 mm long, ovate-lanceolate. Spikes usually 5-10 cm long, lax below. Bracts often c. as long as corolla-tube; bracteoles absent. Calyx 2-segmented, each segment, ovate-lanceolate, rarely shortly and unequally 2-fid above, c. as long as or a little shorter than the bract. Corolla 15-18 (-20) mm long, campanulate, curved above at the back, neither constricted nor inflated below, straight, glandular-pubescent, pale to orange or reddish-brown; lobes unequal, upper erect, sub-hooded to straight, short, lower sub-spreading, crenulate. Stamens inserted below on the corolla-tube, a little above the base; filaments glabrous, except the base; anthers sparsely pubescent to glabrous. Stigma-lobes contiguous, reddish-brown. Capsule 6-10 mm long, ovoid.

Herbs 35-65 cm tall, glandular pubescent. Stems erect, thick. Leaves ovate or ovate-lanceolate, 2-3 cm X 6-8 mm, along with bracts, calyx, and corolla lobes glandular pubescent at margin and abaxially. Inflorescences spicate, 10-22 cm, many flowered; bract lanceolate, 2-2.5 cm, apex long acuminate or caudate-acuminate; bractlets absent. Calyx usually 2-parted to base; segments ovate, oblong, or lanceolate, 1-1.5 cm, entire or irregularly 2-lobed; lobes lanceolate, unequal. Corolla usually pinkish white or whitish, campanulate, slightly curved, 2-2.5 cm; tube enlarged; upper lip entire or emarginate; lower lip slightly shorter than upper; lobes subrounded, ca. 3 mm in diam., dentate, villous. Filaments 0.9-1.2 cm, base sparsely pubescent, glandular pubescent upward; anthers oblong, ca. 1.5 mm, pubescent. Pistil 1.6-1.8 cm; ovary oblong, densely glandular pubescent. Style ca. 1 cm, densely glandular pubescent; stigma usually red, 2-lobed, lobes semirounded. Capsule oblong, 1-1.2 cm X ca. 3 mm. Seeds oblong, ca. 0.4 X 0.2 mm. Fl. Apr-Jun, fr. Jul-Aug. 2n = 38.

Europe, N., C. & S. W. Asia, Afghanistan, Pakistan, Himalaya (Kashmir to Nepal), Tibet.

Distribution: Most of Europe, C. and N. Asia, S.W. Asia, Afghanistan, Pakistan, Kashmir to Tibet.

NW Sichuan, SE Xizang [Afghanistan, Kashmir, Nepal, Pakistan, Turkmenistan; SW Asia, Europe].

2300-3400 m

Slopes, valleys, roadsides; 2500-3700 m.