Marrubium 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 : 137

5. Marrubium L. 2

Perennial herbs. Bracteoles usually present, ascending from a deflexed base. Calyx narrowly obconical, usually 10-veined, with 5-10 teeth; tube densely hairy inside at the mouth. Corolla 2-lipped; upper lip straight, 2-fid; lower lip 3-lobed; tube included in calyx, with an uneven ring of hairs or glabrous inside. Stamens parallel, the outer pair the longer, all included in the corolla-tube; anther-cells diverging. Nutlets truncate at apex.

1 Calyx with 8-10 equal or unequal teeth

2 Calyx-teeth straight; leaves oblong-ovate 11. pestalozzae 2 Calyx-teeth hamate; leaves broadly ovate to orbicular

3 Calyx-teeth 10, equal; petioles of lower leaves usually shorter than lamina 10. vulgare 3 Calyx-teeth 10, 5 longer alternating with 5 shorter; petioles of lower leaves usually longer than lamina 12. alternidens 1 Calyx with 5 ± equal teeth

4 Calyx exceeding corolla, with teeth usually at least as long as tube

5 Calyx-teeth 1-1-5 mm wide at base, lanceolate, rigid in fruit; verticillasters with not more than 12 flowers;

corolla purple 8. alysson 5 Calyx-teeth less than 1 mm wide at base, subulate, not rigid in fruit; verticillasters many-flowered; corolla yellow

6 Calyx-tube 4-5-5(-6) mm; leaves orbicular, regularly and lightly crenate, densely white-lanate beneath 5. velutinum 6 Calyx-tube 6-8 mm; leaves oblong-ovate to elliptical,

irregularly and rather deeply crenate, densely greyish hairy beneath 6. friwaldskyanum 4 Calyx not exceeding corolla, with teeth shorter than tube

7 Lower leaves reniform to reniform-orbicular, cordate at base, the petiole longer than lamina; corolla pink to lilac

8 Leaves densely white-lanate on both surfaces; bracteoles conspicuous, plumose 4. supinum 8 Leaves appressed-hairy above, more densely so beneath;

bracteoles inconspicuous, not plumose 7. leonuroides 7 Leaves oblong to ovate to suborbicular, cuneate at base, the petiole shorter than lamina; corolla white to yellow

9 Stems with most branches patent; verticillasters with not more than 10 flowers 9. peregrinimi 9 Stems unbranched or the few branches erect; verticillasters with more than 10 flowers

10 Corolla-tube narrowing gradually to base; lateral lobes of lower lip almost equalling the middle lobe 3. incanum 10 Corolla-tube abruptly contracted below middle; lateral lobes of lower lip much smaller than the middle lobe

11 Cauline leaves broadly ovate to suborbicular; corolla yellowish 2. cylleneum 11 Cauline leaves oblong to ovate-oblong; corolla white

1. thessalum