Sideritis arborescens Salzm. ex Benth.
Spa.: Calaminta real, zahareña fina, zahareña basta
Subshrub, hermaphrodite, up to 80(100) cm in height, erect, ramose. Woody stems at least in its lower half; young stems fairly hairy, at least in the middle and upper parts, with long hairs (generally more than 1 mm). Leaves 18-30 × 1.2-11 mm, opposite, simple, from lanceolate to narrowly obovate, with 5-7 teeth on either side, slightly hairy. Inflorescences terminal, in spikes of verticillasters, which are spaced apart and usually with 6 flowers. Bracts of verticillasters 6.5-10 × 8-15 mm, dentate, spinescent. Calyx campanulate 6-8.5 mm, with 5 sepals fused almost entirely, with triangular teeth, hairy, with long hairs and stalked glands. Corolla 7.5-10 mm, yellow, bilabiate, with tube 6.5 mm. Fruit ovoid, very small (2-2.5 mm), included in the calyx, composed of 4 very small nutlets, from subtrigone to subovoid. 2n = 30, 50; n = 12, 13, 15.
Flowering:
March to July.
Fruiting:
May to September.
Habitat:
Cleared forests and thickets on calcareous or siliceous soils, sandy, stony, in dry environments and from almost sea level to about 1,200 m in altitude.
Distribution:
S of the Iberian Peninsula, Morocco and N of Algeria.
Observations:
Polymorphic species, of which several subspecies, varieties and forms have been described, many of them not clearly defined. Currently (Index SFAN, 2012) there are 3 subspecies accepted in North Africa: subsp. ortonedae (Font Quer) Maire, in N of Morocco and Algeria, and subsp. maireana (Font Quer & Pau) Socorro & Arreb. and subsp. antiatlantica (Maire) Romo, endemic to Morocco.
Conservation status:
Rare species with a small distribution area. Currently, it has not been assessed at a global level in the IUCN Red List of Threatened Species.