Rosa L.
Genus composed of about 360 species, mainly Asian, but also well represented in other temperate and cold zones of the Holarctic. In North Africa it is represented by 12 species, of which 1 is taxonomically doubtful (R. mesatlantica), 3 more (R. montana, R. stylosa and R. abietina) are taxa with alpine distribution and therefore their presence on the African territory should probably be verified, and 7 microspecies that belong to the complex group of R. canina in a broad taxonomic sense. This is probably the most difficult genus to treat, even for specialists. Furthermore there is a relatively high number of species, with only slight differences, along with the problem of frequent hybridisations and introgressions. Only in North Africa, more than 100 infraspecific taxa have been described, many of which could hardly be differentiated and accepted as valid today.
The presence and distribution of two species in the region should be reviewed:
R. mesatlantica H.Lindb. described as a subshrub with leaves with 5 leaflets, ± orbicular, with twice serrated margin, pubescent on both sides, without glands (except for the midrib on the underside), flowers solitary or in pairs, external sepals lobed, glandular margins, and smooth urceolus; located in the cedar forests of the northern Middle Atlas (Ras el Ma).
R. montana Chaix ex Vill. is a shrub up to 3 m in height, leaves with 5-7 ± orbicular leaflets, with twice serrated margin, glabrous on both sides, flowers usually solitary, sepals ± lobulate, ending in a foliaceous appendage, glandular on the dorsal side, persistent and upright on the mature urceolus; located in Algeria in the central Tellian Atlas [Jebel Megriss (near Constantine), Jebel Zaccar (Miliana), Djurdjura Massif] and Saharan Atlas (Jebel Bu Kherouf, near Aflou).
These native roses cited above should not be confused with other roses that appear in the territory subspontaneously, usually originating from ornamental and/or aromatic crops, such as R. gallica L. or R. moschata Herrm. In Morocco, particularly in the region of Kalaat M’Gouna (southern slope of the High Atlas), there is a long tradition (since the Middle Ages) of cultivation of R. damascena Mill., from which around 4,000 tons of petals are produced per year, mainly for the cosmetics industry and for the production of rosewater.
The key given below is for the species traditionally considered natives in North Africa, including some very rare and/or doubtful, to contribute towards their search and determination.
Kurtto, A. 2009. Rosaceae (pro parte majore). In: Euro+Med Plantbase – the information resource for Euro-Mediterranean plant diversity.
Omar, K., Nagy Sayed, A.M., Abdallah, A.M, Aboelfetoh, G.M. & Abdallah, M. 2016. Ecological and Conservation Assessment of Rosa arabica in St Katherine– Egypt. 84 pp.
Omar, K. & Elgamar, I. 2021. Conservation of challenging endemic plant species at high risk of extinction in arid mountain ecosystems: a case study of Rosa arabica Crép. in Egypt. Journal of Mountain Science 18(10): 2698-2721. DOI:10.1007/s11629-021-6750-2
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Key to species
1 Flowers with styles fused into column (when mature, styles may be slightly free). Sepals caducous 2
1 Flowers with free styles. Sepals caducous or persistent 3
2 Leaves persistent throughout the year, with (3)5 leaflets. External sepals usually entire Rosa sempervirens
2 Leaves deciduous, with 5-7 leaflets. External sepals with 3-8 lobes Rosa stylosa
3 Branches densely covered in prickles and bristles. Sepals entire. Rosa spinosissima
3 Branches with spaced prickles (except in young branches of R. sicula, where prickles can also be very dense) ± curved. External sepals ± lobulate 4
4 Leaflets covered with numerous odorous glands on the underside 5
4 Leaflets with no glands on the underside or, if with some glands, not odorous 7
5 Petals pink. Sepals persistent or very late caducous. Styles villous 6
5 Petals pinkish-whitish or white. Sepals promptly caducous. Styles glabrous or glabrescent 8
6 Leaflets > 16 mm, plant robust up to 3 m in height Rosa arabica
6 Leaflets up to 16 mm, plant not robust up to 0.8(1) m in height Rosa sicula
7 Leaflets orbicular, glabrous on both sides. Fruit with persistent sepals, upright Rosa montana
7 Leaflets (at least upper leaflets) oval-elliptic, acute or obtuse, hairy or glabrous, caducous or, when persistent, with sepals arched backwards towards fruit 9
8 Leaflets with cuneiform base. Pedicels not glandular. Sepals without glandular dorsal side Rosa agrestis
8 Leaflets with ± rounded base. Pedicels glandular. Sepals with glandular dorsal side Rosa micrantha
9 Subshrub up to 0.5 m in height, with suborbicular leaflets, upper leaflets oval-elliptical, pubescent on both sides Rosa mesatlantica
9 Shrubs up to 3 m in height, with ± elliptic leaflets, glabrous or ± hairy 10
10 Leaflets ± oval-rounded, small. Prickles shorter than length of their base. External sepals with wide lobes, ± lanceolate Rosa abietina
10 Leaflets oval-lanceolate, larger. Prickles longer than length of their base. External sepals with narrow lobes, ± linear-lanceolate 11
11 Margin of leaflets single or twice serrated, usually without glands. Stipules of upper leaves 12-20 mm Rosa canina
11 Margin of leaflets twice serrated, glandular. Stipules of upper leaves 8-12 mm Rosa pouzinii
Key to the "microspecies" of the R. canina group
1 Shrubs glabrous 2
1 Shrubs tomentose 5
2 Leaflets with single serrated margin 3
2 Leaflets with twice serrated margin 4
3 Pedicels without glands Rosa canina
3 Pedicels with glands Rosa andegavensis
4 Pedicels without glands Rosa squarrosa
4 Pedicels with glands Rosa blondeana
5 Leaflets with single serrated margin 6
5 Leaflets with twice serrated margin. Pedicels without glands Rosa obtusifolia
6 Pedicels without glands Rosa corymbifera
6 Pedicels with glands Rosa deseglisei
Updated by: N. Hidalgo.