Sideritis arborescens, Salzm. ex Bentham

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 : 140

3. S. arborescens Salzm. ex Bentham , Lab. Gen. Sp. 579 (1834).

Shrub up to 100(-200) cm, with erect, herbaceous flowering stems up to 50 cm. Leaves 15-35 x 1-10 mm, oblonglanceolate to elliptical, rarely linear, often remotely dentate. Verticillasters 4-20, usually distant, 6- to 10-flowered. Lower bracts 8-15x8-20 mm, about equalling calyx, cordate-ovate, incise-dentate, glandular. Calyx 7-9 mm, glandular, with a ring of hairs inside. Corolla 8-13 mm, yellow or pale pink. Rocky and bushy places. S. Spain. Hs. A variable species which cannot always be clearly separated from 11, 13 and large-flowered variants of 4. 1 Leaves 1-2 mm wide, linear, entire or with few obscure teeth;

corolla pale pink (b) subsp. luteola 1 Leaves 2-10 mm wide, linear-lanceolate to oblong-lanceolate or elliptical, entire to serrulate or with few, short lobes;

corolla usually yellow 2 Stem glabrous or sparsely hairy; leaves entire, crenatedentate or serrulate; calyx 7-8 mm (a) subsp. arborescens 2 Stem hairy, usually glandular; leaves with few coarse teeth or shallow lobes; calyx c. 9 mm (c) subsp. paulii