IDENTIFICATION KEY OF OROBANCHE L. SPECIES

1. Corolla with reddish or brown glandular hairs ............................................................. Orobanche alba Willd.

— Corolla without dark glandular hairs ........................................................................................................... 2

2. Corolla inflated under the stamen insertion, narrowed distally .................................................................... 3

— Corolla of the same diameter throughout, or slightly widened distally ......................................................... 5

3. Corolla yellow with purple veins; calyx teeth linear; stigma yellow or white .......................... O. hederae Duby

— Corolla lavender; calyx teeth triangular; stigma pale violet ........................................................................... 4

4. Plant 10-30 cm tall, inflorescence dense, corolla 15-18 mm long, anthers glabrous ..................... O. cernua L.

— Plant 35 or more cm tall, inflorescence lax, corolla 19-22 mm long, anthers hairy ............... O. cumana Wallr.

5. Calyx teeth linear, twice as long as the tube ................................................................................................. 6

— Calyx teeth triangular, long at most, a little more than the tube .................................................................. 9

6. Corolla distally dark red ......................................................................................................... O. foetida Poir.

— Corolla whitish or yellowish with violet veins .............................................................................................. 7

7. Corolla lips curved outwards .............................................................................................. O. crenata Forssk.

— Corolla lips straight ..................................................................................................................................... 8

8. Corolla lobes with entire margin .................................................................. O. artemisiae-campestris Gaudin

— Corolla lobes crenulate ................................................................................................... O. calendulae Pomel

9. Corolla> 20 mm long ............................................................................................................................... 10

— Corolla <20 mm long ............................................................................................................................... 12

10. Dorsal line of the corolla regularly curved ............................................................... O. rapum-genistae Thuill.

— Dorsal line of the corolla strongly curved near the base, almost straight distally ......................................... 11

11. Middle lobe of the lower corolla lip larger than the lateral lobes ........................................ O. variegata Wallr.

— Middle lobe of the lower corolla lip smaller than or subequal to the lateral lobes ..................... O. gracilis Sm.

12. Corolla geniculate above the base .................................................................................. O. amethystea Thuill.

— Corolla with dorsal line regularly curved ................................................................................................... 13

13. Corolla narrow (width / length = 0.2), distally red; stem bracts linear ........................................................ 14

— Corolla wider (width / length ≥ 0.25), distally whitish with violet veins; stem bracts triangular .................. 15

14. Corolla lips straight, throat rounded ............................................................................. O. sanguinea C. Presl

— Corolla lips curved outwards, throat flattened ................................................................. O. densiflora Bertol.

15. Spike dense, with ± contiguous flowers ................................................................................... O. litorea Guss.

— Spike lax, with clearly spaced flowers ......................................................................................................... 16

16. Corolla woolly on the upper lip; style pubescent ............................................................... O. pubescens d’Urv.

— Corolla glabrous or hairy; style subglabrous ............................................................................................... 17

17. Flowers erecto-patent; filaments densely hairy at the base ............................................... O. canescens C. Presl

— Flowers patent; filaments scarcely hairy at the base .................................................................... O. minor Sm.