Cistus L.
Genus with about 52 species distributed mainly through the Mediterranean and Macaronesia regions. In North Africa it is represented by 12 species (13 species if C. varius is accepted at a species level) distributed throughout the Mediterranean area.
The rock roses can be hybridized between them forming specimens like those of the photos here exposed. They are not at all common but they can be seen here and there by their parent distribution areas.
Soriano, I. 2008. Algunos tipos de cistáceas béticas y rifeñas en los herbarios BC, MA y MAF. Collectanea Botánica (Barcelona) 27: 29-35.
Guzmán, B., Lledó, MD. & Vargas, P. 2009. Adaptive Radiation in Mediterranean Cistus (Cistaceae). PLoS ONE 4(7): e6362. doi:10.1371/journal.pone.0006362
Key to species
1 Leaves lanceolate to linear, 5 to 10 times longer than wide. Petals white 2
1 Elliptical, ovate or heart-shaped leaves, up to 3 times longer than wide. Petals white or pinkish 5
2 Leaves narrowly linear, 1-1.5 mm wide and 12 to 17 mm long, revolute margin, with a single nerve, very similar to that of a rosemary, although without its characteristic aroma Cistus clusii
2 Leaves linear-lanceolate, at least 3 mm wide 3
3 Leaves 6-20 x 40-80 mm Cistus ladanifer
3 Leaves smaller, 3-6 x 25-50 mm 4
4 Twigs glabrous or subglabrous, greenish or somewhat reddish Cistus monspeliensis
4 Twigs villous and silky, with a silvery-whitish aspect Cistus munbyi
5 Leaves with three main nerves, longitudinal and parallel to each other 6
5 Leaves with pinnate nerves 10
6 Leaves glabrous and dark green on the adaxial surface, tomentose white Cistus laurifolius
6 Leaves gray tomentose on both surfaces. Petals white or pinkish 7
7 Leaves pedunculated. Petals pinkish Cistus parviflorus
7 Leaves sessile 8
8 Leaves flattened. Non-aromatic plants. Petals pinkish Cistus albidus
8 Leaves with wavy margin. Aromatic plants 9
9 Leaves non-connate. Petals white Cistus varius
9 Leaves connate. Petals pinkish Cistus crispus
10 Leaves 40 to 100 mm long x 30-70 mm wide, ovate to ovate-lanceolate, cordate, plants without stellate hairs. Petals white Cistus populifolius
10 Smaller and differently shaped leaves, plants with stellate hairs 11
11 Lower leaves petiolate, upper ones sessile. Petals pinkish Cistus heterophyllus
11 All the leaves petiolate 12
12 Leaves more or less elliptical, with wavy margin. Petals pinkish Cistus creticus
12 Leaves oval, with flat margin. Petals white Cistus salviifolius
Updated by: F. Alcaraz & Jesús Charco.