'Rosa nanothamnus Boulenger' rose References
Book (1 May 2003)
from the description of Rosa giraldii Crépin:
Rosa nanothamnus Boulenger (Bull. Jard. Bot. État 13: 206. 1935), described from Xinjiang, is very similar to R. giraldii and differs only in having larger prickles, equaling or longer than the largest leaflets, and crenate leaflet margins. Further study is needed to ascertain whether R. nanothamnus should be treated as a separate species or a fourth variety of R. giraldii.
Article (magazine) (2002) Page(s) 358-359.
Dwarf Rose (Rosa nanothamnus Bouleng.). This species grows on stony slopes of the mountains. It is a xero-mesophytic, divaricate-branching shrub, 1.5 to 2.5 m high with thin, straight thorns widened at the base. Compound leaves have five to nine orbicular or obovate leaflets, 1.5 cm long, with both sides mostly pubescent. Pinkish-white flowers are borne in inflorescences of two to three. Red fruits are globular or ovate, with thin glandular-bristles.
Article (magazine) (2002) Page(s) 355.
R. nanothamnus (Dwarf rose). Distribution: Dzhungarskei, Talasskei Alatau, Karatau. Use: Ornamental, honey plant.
Book (1996) Page(s) 112.
R. nanothamnus Central Asia. Pink, solitary or in 2-3s on short stalks, red, ovoid or globular fruit. Very small, leathery leaflets. Pointed prickles, uniform and fine. Spreading bushes (after Saakow). Raised from seed by B. Müller, Palmengarten.
Book (1988) Page(s) 23. Includes photo(s).
Rosa nanothamnus Boulenger (R. webbiana var. microphylla Crép.) A dwarf, very prickly shrub up to 50 cm high, with long straight spines. Leaflets usually 5 (-9), ovate or obovate, 3-15 mm long, glabrous or pubescent. Flowers solitary up to 3.75 cm in diameter. Hips globose or ovoid, 10-12 mm long, sepals persistent. Native of central Asia, from Tien Shan and Pamir-Alai to Afghanistan and Kashmir, on dry rocky hillsides. Requires full sun and exposure to flower well. This is a dwarf, small-leaved form of R. webbiana.
Article (magazine) (1975) Page(s) 59-66.
Abstract from Blackwell Synergy website: "Rosa nanothamnus has uncertain affiliations within the genus Rosa. However, evidence is presented that its system of inheritance is of the distinctive and singular type found in the section Caninae .It is considered that this complex system is unlikely to have arisen purely by fortuitous hybridization but is, in fact, highly evolved. Species which share the canina-type system of inheritance are interpreted as a closely related group. Rosa nanothamnus is therefore placed in section Caninae.
Analysis of chromosomes at pachytene in meiosis in Rosa nanothamnus showed that there were 7 bivalents and 14 univalents. It is suggested that the genes which restrict chromosome pairing in this species, and presumably in the Caninae generally, affect synapsis of chromosomes rather than the formation of chiasmata."
Book (1971) Page(s) 348.
R. nanothamnus Bouleng. in Bull. Jard. Bot. de I'Etat Bruxelles XIII, fasc.3 (1935) 206.- R. webbiana Crep. in Bull. Soc. Bot. Belg. XIII (1874) 273, p. p., non Wall, ex Royle. — R. webbiana var. microphylla Crep., I.e., 276.- Ic: Bouleng., I.e.; 208, f . 2 (ram. florif.).
Shrub, dwarf, usually 15— 30 cm high, with very short flower -bearing branches; prickles erect, rarely curved, sometimes directed upward, remote or in pairs, often thin and abruptly broadened at base, the longest as long as or longer than the largest leaflets, often yellow; small pricklets absent, with the exception of turions which may bear strong prickles, in exceptional cases some branches with few prickles; leaves very small, 10—55 mm long; leaflets 5—9, remote, often approximate, sessile or petioluled, orbicular, ovate or obovate, sometimes truncate, 3— 15 mm long, glabrous or pubescent either on both sides or only beneath; teeth simple, sometimes some with 2—3 mucros; petioles glabrous or pubescent, somewhat glandular at times, with small erect prickles or without prickles; stipules connate, narrow, with triangular or acute divergent auricles, margin frequently glandular. Flowers often solitary, pedicels 1— 17 mm long, glabrous, smooth or glandular; sepals nearly always shorter than petals,
in bud not exceeding or slightly exceeding petals, entire or narrowing at base, mucronate, more or less broadened, with spatulate or foliate tip, dorsally glandular or glandular -hispid, rarely smooth, persistent; corolla 20— 35 mm in diameter; petals pink or white, barely incised; opening of disk one -third to two-fifths its diameter; style lanate -villous, stigma head flattened, capitate, conical or clavate; fruit globose or ovoid, sparsely glandular -hispid or smooth, 10—12 mm long, crowned by spreading or ascending sepals. June— July.
Centr. Asia: T. Sh., Pam.-Al. Gen. distr.: see (s. str.), probably endemic. Described from Fergana, Arslanbob. Type in in Brussels, cotype in Leningrad.
Note. Boulenger's delimitation of this species is much too wide. In his view species Nos. 23, 24, 25, 27, and 28 [R. maracandica, R. kuhitangi, R. bellicosa, R. hissarica, R. altaica] should all be included in R. nanothamnus.
Magazine (1967) Page(s) 51. Includes photo(s).
[From article "Chromosome studies and evolution in Rosa" by G. D. Rowley, Vol. 37, pp. 45-52:]
Cytological study of Boulenger's Rosa nanothamnus ....shows it to be a tetraploid of the canina-type, not a diploid as was previously imagined (fig. 5). Boulenger...cites a distribution range for nanothamnus from Asia Minor to Western China, extending to Sze-Chuan where Rosa chinensis also occurs....
I should like to close by thanking Andrew Roberts for the use of his photographs and unpublished data on Rosa nanothamnus.
Article (magazine) (1967)
Cytological study of Boulenger's Rosa nanothamnus (Roberts, unpublished) shows it to be a tetraploid of the canina-type, not a diploid.
Book (1937) Page(s) 74.
microphylla Crép. (form of Webbiana Wll.) [ploidy] 14