Biscutella L.

78. Biscutella L. 1

Herbs or small shrubs with entire to pinnatifid leaves. Petals usually clawed, yellow. Fruit a strongly compressed didymous silicula, indéhiscent but with the 1-seeded loculi eventually breaking away from the axis; valves glabrous or with simple or davate hairs; style long. Seeds unwinged.

The taxonomy of this genus is made difficult by the relative uniformity of most of the floral and fruiting characters and by the unreliability of those that do vary. Reliance has to be placed on vegetative features, but there is inadequate knowledge about their range of plasticity. The two available monographs differ widely in their treatment, the one lumping, the other splitting. A narrow species concept is adopted here, largely to force attention on the variation in the genus, so that a future synthetic treatment may be possible. Most of the species recognized here have a characteristic facies and a well-circumscribed distribution. Intermediates between some of them do occur but to treat them as subspecies would make the classification unwieldy and such treatment has been deferred until further information becomes available.

Literature: E. Malinowski, Bull. Int. Acad. Sci. Cracovie 1910: 111-39 (1910). B. Machatschki-Laurich, Bot. Arch. (Königsberg) 13: 1-115 (1926).

1 Petals up to 15 mm, conspicuous, long-clawed, patent; silicula with a diaphanous margin

2 Silicula not emarginate at apex, the wings excurrent with the style 40. auriculata 2 Silicula emarginate at apex, the wings not excurrent with the style 41. cichoriifolia 1 Petals not more than 8 mm, small or medium , short-clawed, erect; silicula with a narrow membranous margin

3 Petals abruptly contracted into a claw, auriculate-dilated above the base

4 Leaves glabrous to hirsute, not tomentose

5 Basal leaves ovate, slightly longer than wide

(4-6). variegata group 5 Basal leaves oblong, longer than wide

6 Leaves entire or slightly sinuate-dentate 1. laevigata 6 Leaves deeply toothed, lobed or pinnatifid

7 Dwarf plants (10-30 cm); leaves 1-5 cm

8 Leaves less than 1 cm wide, 1-3 cm long

9 Silicula up to 6 mm wide; basal leaves narrowly linear to oblong 12. glacialis

9 Silicula more than 7 mm wide; basal leaves obovatelanceolate 13. brevifolia

8 Leaves more than 1 cm wide, usually 4 cm long or more

10 Silicula 5 x 8-8-5 mm

11 Basal leaves with 1-2 teeth on either side 14. cuneata

11 Basal leaves with 3-4 teeth on either side 15. rotgesii

10 Silicula 6-7 x 9-11 mm

12 Basal leaves with few, weak lobes 31. intermedia

12 Basal leaves deeply lobed or toothed

13 Basal leaves subpinnatifid 21. brevicaulis

13 Basal leaves with 1-3 large teeth 19. divionensis 1 Medium to large plants ((20-)30-60 cm or more); leaves

4-14 cm

14 Basal leaves 0-2-0-5 cm wide, excluding teeth

33. valentina

14 Basal leaves more than 0-5 cm wide

15 Basal leaves pinnatifid

16 Petals 3 mm; silicula 3-5-4 x 7 mm 17. sclerocarpa

16 Petals at least 4 mm; silicula 5-7 x 8-13 mm

17 Leaf-lobes more than 4 on each side, with some small lobes intermixed with the large ones

18 Leaves setose 29. mediterranea

18 Leaves pubescent but not setose

(22-27). coronopifolia group

17 Leaf-lobes 4 or fewer on each side, without smaller lobes intermixed

19 Lobes of basal leaves acute

20 Leaf-lobes recurved; caul ine leaves numerous

(22-27). coronopifolia group

20 Leaf-lobes not recurved; cauline leaves few

30. nicaeensis

19 Lobes of basal leaves obtuse

21 Leaf-lobes broadly triangular, undulate

32. guillonii

21 Lobes narrower, not undulate

(22-27). coronopifolia group

15 Basal leaves with large and usually deep teeth, or sinuate-dentate, but not pinnatifid

22 Cauline leaves absent or all minute 2. scaposa

22 Cauline leaves well developed, decreasing in size towards apex of stem

23 Silicula 4-5 x 7-9 mm

24 Stems densely leafy; flowers in dense corymbs

18. arvernensis

24 Stems sparsely leafy; flowers in long racemes

16. lamottii

23 Silicula 6-12 x 9-14 mm

25 Leaves deeply and regularly toothed 28. lusitanica

25 Leaves sinuate-dentate, shallowly toothed or subentire

26 Cauline leaves wide, dilated at base 20. controversa

26 Cauline leaves not dilated

27 Leaves with 2 glands at base 1. laevigata

27 Leaves without glands at base

28 Basal leaves polymorphic, spathulate to lanceolate, sinuate or entire 7. gredensis

28 Basal leaves all ± spathulate, shallowly dentate

29 Stems 20-40 cm, not flexuous 8. neustriaca

29 Stems 40-65 cm, flexuous 3. flexuosa 4 Leaves tomentose 30 Silicula 8-11 x 12-19 mm 10. vincentina 30 Silicula 3-6 x 7-10 mm 31 Inflorescence 10-15 cm, compound-paniculate 9. frutescens 31 Inflorescence less than 8 cm, compact 11. sempervirens 3 Petals gradually attenuate at base, not auriculate 32 Staminal filaments with a wide membranous wing

34. microcarpa 32 Staminal filaments unwinged 33 Leaves lyrate 34 Annual; silicula 3-5-5 x 7-10 mm 37. lyrata 34 Perennial; silicula 6-7 x 11-13 mm 39. radicata 33 Leaves toothed or entire, not lyrate 35 Infructescence lax; pedicels patent 35. baetica 35 Infructescence dense; pedicels erecto-patent

36 Silicula 4 x 6-8 mm 36. eriocarpa 36 Silicula 4-5-7 x 9-5-12 mm 38. didyma