Sideritis L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1972, Flora Europaea. Volume 3. Diapensiacea to Myoporaceae, Cambridge: Cambridge University Press : 138-140

6. Sideritis L. 1

Annual or perennial herbs, or small shrubs. Verticillasters 2- to many-flowered; bracteoles absent. Calyx campanulate, 10- veined, 5-toothed; teeth equal, or the upper larger than the 4 lower. Corolla usually yellow; tube not exceeding calyx; upper lip patent, more or less flat, entire to 2-fid; lower lip 3-lobed. Stamens included in corolla-tube. Nutlets rounded at apex. A taxonomically difficult genus, requiring an extensive experimental investigation. Specific limits in Sect. Sideritis , and to a lesser extent in Sect. Empedoclia , are often obscure. Interspecific hybrids within Sect. Sideritis have been recorded from many localities in Spain and it seems probable that much of the taxonomic difficulty is due to the occurrence of these hybrids and possibly hybrid swarms.

Literature: P. Font Quer, Trab. Mus. Ci. Nat. Barcelona 5(4) (1924).

1 Calyx ± 2-lipped, the upper tooth longer and wider than the 4 lower teeth; annual

2 Stem with short glandular hairs; upper calyx-tooth narrowly lanceolate; corolla yellow with black lips 26. lanata 2 Stem without glandular hairs; upper calyx-tooth ovate; corolla yellow, purple or white

3 Calyx with prominent veins, not saccate at base; teeth patent in fruit 27. romana 3 Calyx without prominent veins, saccate at base; teeth curved in fruit 28. curvidens 1 Calyx ± actinomorphic, the teeth all equal

4 Annual

5Leaves 2-8 mm wide, oblong-lanceolate 25. montana 5 Leaves 8-15 mm wide, ovate 26. lanata 4 Shrub, or perennial herb woody at base

6 Bracts entire

7 Middle and lower leaves rounded or cordate at base, semiamplexicaul and often perfoliate 24. perfoliata 7 Middle and lower leaves attenuate at base, not semiamplexicaul and never perfoliate

8 Bracts narrowly ovate to triangular-cordate, not conspicuously acuminate or cuspidate; calyx 4-8 mm; corolla 8-10 mm

9 Verticillasters distant; calyx without a ring of hairs inside

19. incana 9 Verticillasters crowded; calyx with a l ing of hairs inside

10 Leaves narrowly lanceolate, glabrescent to villous; corolla yellow, sometimes tinged with purple

8. hyssopifolia 10 Leaves oblong- to obovate-spathulate, densely white tomentose-lanate or sericeous-lanate; corolla purple

18. stachydioides 8 Most bracts broadly ovate to suborbicular with a distinct acumen or cusp; calyx 7-12 mm; corolla (9-)10-15 mm

11 Middle bracts usually equalling or shorter than flowers and often shorter than calyx; verticillasters usually distant 21. syriaca 11 Middle bracts exceeding flowers; verticillasters usually crowded to form a dense spike

12 Middle bracts with acumen 4-10 mm 22. clandestina 12 Middle bracts with acumen 2-4 mm 23. scardica 6 Bracts coarsely toothed and often spiny

13 Most leaves spinose-dentate with pungent lateral teeth

14 Plant with dense, short glandular papillae, at least on the upper part of the stem; verticillasters distant 16. ilicifolia 14 Plant glabrescent to villous-tomentose, sometimes also glandular, hairy; verticillasters crowded into dense spikes

15 Middle cauline leaves with 2-6, usually very coarse, divaricate lateral spines 14. spinulosa 15 Middle cauline leaves with at least 20 appressed lateral spines 15. serrata 13 Leaves entire or toothed but the lateral teeth not pungent

16 Calyx without a ring of long hairs inside

17 All leaves entire, or rarely with few small teeth; bracts with up to 11 teeth 19. incana 17 Lower leaves crenate-dentate; bracts incise-dentate, usually with more than 11 teeth 20. lacaitae 16 Calyx with a ring of long hairs inside

18 Corolla white, sometimes with reddish markings on the lips 19 Erect shrub up to 100 cm; most verticillasters crowded into a dense spike; corolla c. 6 mm, not or scarcely exceeding calyx 2. foetens 19 Herb or dwarf shrub up to 30 cm; most verticillasters distant; corolla 7-10 mm, distinctly exceeding calyx

17. leucantha 20 Stem with at least some long, straight, patent hairs; lower bracts 8-20 mm wide 4. hirsuta 20 Stem with short, crispate hairs; lower bracts 6-8 mm

wide 17. leucantha 18 Corolla yellow, pink or purple, sometimes with a white upper lip

21 Calyx 12-17 mm; corolla 14-20 mm

22 Leaves45-90 mm; corolla pale yellow inside 1. grandiflora 22 Leaves not more than 35 mm; corolla tinged with dark brown or purple inside 5. endressii 21 Calyx usually not more than 12 mm; corolla usually not more than 13 mm

23 Bracts shorter than calyx

24 Leaves coarsely incise-dentate or -crenate

25 Stem tomentose with crispate and appressed hairs

6. scordioides 25 Stem hirsute with numerous ± straight hairs 4. hirsuta 24 Leaves entire or with few small teeth

26 Stem not more than 15cm; verticillasters 1-3,

usually distant 7. glacialis 26 Stem up to 30 cm; verticillasters 5-15, mostly crowded 8. hyssopifolia 23 Bracts equalling or exceeding calyx

27 Verticillasters crowded into a dense spike (sometimes the lowest 1-2 distant)

28 Stem and leaves densely white tomentose-lanate or sericeous-lanate; corolla purple 18. stachydioides 28 Stem and leaves green or grey-green, glabrous to tomentose or villous; corolla yellow, sometimes tinged with purple

29 Lower leaves cordate or rounded at base, crenateserrate; petiole as long as or almost as long as lamina 9. ovata 29 Lower leaves attenuate at base, entire or with few remote teeth or coarsely incise-dentate or

-crenate; petiole absent or short

30 Shrub up to 2 m 3. arborescens 30 Perennial herb with woody base, not more than

80 cm

31 Leaves 1-4 mm wide

32 Verticillasters (2—)3—5; corolla dark brown inside 12. javalambrensis 32 Verticillasters 4-15; corolla yellow or purplish inside

33 Bracts with few aristate teeth 8. hyssopifolia 33 Bracts coarsely spinose-dentate with numerous teeth 10. linearifolia 31 Leaves more than 4 mm wide

34 Calyx 6-8 mm; leaves glabrescent to villous

8. hyssopifolia 34 Calyx 9-10 mm; leaves densely villoustomentose 15. serrata 27 Verticillasters ± distant, all except the uppermost with stem visible between each verticillaster

35 Leaves linear or linear-lanceolate, mostly at least 5

times as long as wide

36 Stem glabrous or sparsely hairy; calyx 7-9 mm

3. arborescens 36 Stem tomentose; calyx 5-7 mm 11. angustifolia 35 Leaves less than 5 times as long as wide

37 Shrub up to 200 cm 3. arborescens 37 Perennial herb with woody base, not more than

60 cm

38 Stem tomentose with crispate and appressed hairs

39 Verticillasters very numerous, many-flowered;

leaves oblong-lanceolate; bracts broadly reniform 12. reverchonii

39 Verticillasters 3-12(-14), 2- to 6-flowered; leaves linear-oblong to obovate; bracts lanceolate-

or ovate-cordate to suborbicular

40 Lower bracts 6-15 x 10-20 mm, similar to the upper; leaves incise-dentate or crenate

6. scordioides

40 Lower bracts 4-10 x 6-8 mm, distinct from the upper; leaves entire to coarsely toothed or shallowly lobed 17. leucantha

38 Stem glabrescent or with at least some ± straight long hairs

41 Calyx 9-13 mm; corolla tinged with dark brown or purple inside 5. endressii

41 Calyx 5-8(-9) mm; corolla not dark-tinged inside 4. hirsuta