Newsletter  (Mar 2010)  Page(s) 11-12.  
 
"Rosa laxa Retzius: Not Always Tetraploid," by Peter Harris

"The laxa Griffith Buck used is from the laxa Niels Hansen had brought to the United States from the Semipalatinsk region of Kazakhstan in 1913.

An accession record at the University of Minnesota Horticultural Research Center conclusively links the laxa used by F.L. Skinner, Percy Wright, Robert Simonet, Griffith Buck, and others to the laxa brought back to the US by Niels Hansen in 1913 and announced and made available to the public by the USDA in early 1927.

In accession record #N2744 in the volume labeled “Fruit Breeding Farm Accessions 1923 – 1950” the Species is listed
as “Laxa Retz” and Source is listed as “from Hansen’s Stock Sioux Falls.” Although Hansen’s personal selection called ‘Semi’ (short for Semipalatinsk, where the seeds were collected) was apparently a light pink, most plants grown from the seeds were white. The chain of transmission of laxa in this case is from Hansen’s program in South Dakota to the Minnesota Fruit Breeding Station (Excelsior, MN) as seeds received on August 23, 1927, and from there through Arthur N. Wilcox in Minnesota to F.L. Skinner in Manitoba and thus to various other rose breeders."
. . . . . . . . .
"In a letter to Griffith Buck (February 22, 1954), Skinner summarized it: 'Morden received their laxa from me and I got it origionally [sic] from Dr. Wilcox of Minnesota who in turn got it from the U.S.D.A so now you have its full history.'”

Article (magazine)  (2009)  Page(s) 30.  
 
R. laxa Retz.   Source RJBM [Collection of Texas A. M. University] Chromosome Number 28

Article (magazine)  (2007)  Page(s) 370, fig. 1.  
 
Rosa laxa typical ploidy 4x

Book  (May 2003)  Includes photo(s).
 
Rosa laxa Retzius 1803
Shrubs 1-2 m tall...prickles in pairs below leaves...yellowish, strongly hooked,...often densely intermixed with small prickles and bristles...leaflets 7-9...margin simply serrate...Flowers often 3-6 in corymb, sometimes solitary, ca. 3 cm in diam...Sepals...densely pubescent...Petals 5, white or pink...Hip red, oblong or ovoid...apex with a short neck and persistent, erect sepals.

Two variants have been identified: Rosa laxa var. laxa and Rosa laxa var. mollis. 'Mollis' has leaflets that are densely pubescent on both leaf surfaces. Rosa gebleriana Schrenk and Rosa soongarica Bunge are both synonyms of Rosa laxa var. laxa.

Populus forests, scrub, valleys, damp grassy places, river and stream sides; 500--1500 m. Xinjiang [Mongolia, Russia (C Siberia); C Asia].

Article (magazine)  (2002)  Page(s) 358.  
 
Lax Rose (Rosa laxa Retz.). This species grows on mountain slopes, forest borders, and banks of rivers and lakes. It is a xero-mesophytic shrub, 2 m high, with thorns that are strong, uncinate-recurved or slightly pointed, and widened at the base. Grayish-green, compound leaves have five to nine leaflets that are ovate, elliptical or oblong, glabrous or slightly pubescent on the under-sides. Pale, pinkish-white flowers are borne three to six in corymbs. Fruits are smooth, globular or elliptical, with persistent sepals. Fruits contain high levels of carotene and vitamin C.

Article (magazine)  (2002)  Page(s) 355.  
 
R. laxa (Lax rose). Distribution: The Altai, Tarbagatai, Dzhungarskei, Zailiyskei, Kundei, Terskei, Talasskei Alatau, Ketmentau. Use: Food, medicinal, ornamental plant; easily cultured.

Website/Catalog  (1992)  
 
R. laxa Retzius 2n=14

Book  (1971)  Page(s) 343-344.  Includes photo(s).
 
R.laxa Retz. in Hoffm., Phytogr. Bl. (1803)39; Wikstr. in Kongl. Vetensk. Akad. Handling. (1820)267; C.A. M., Ueber die Zimmtrosen (1849) 120; Crep. in Bull. Soc. Bot. Belg. XIV (1875) 26; Kryl., Fl. Zap. Sib. VII (1933) 1571.- R. soongarica Bge. ex Ldb., Fl. Alt. vol.11 (1830) 226.- R.alpina Ldb., Fl. Ross. II, 75 p. p., nonL.- R.gebleriana Schrenk in Bull. Phys.-Math. Acad. Sc, St.-Petersb. I (1843) 80; Ldb., Fl. Ross. vol. II (1844) 76. — R. cinnamomea var. soongarica Ldb., I.e. 76.— R.laxa incana Wikstr., 1. c. — R. laxa apubescens et glabra C.A.M., 1. c. — R. cinnamomea var. microcarpa: a puberula et glabra C.A.M., I.e. 29.— Ic: Willmott, The Gen. Rosa VIII (l91l) tab. 53. - Exs.: Kar. et Kir., No. 325 (s.n. R. oxyacantha) et No. 560 (s. n. R. cinnamomea).
Shrub, to 2 m high, stem arcuate, with strong branches; bark nearly always green, glaucescent (at least when young); prickles sparse, rather large, strongly arcuately downcurved, flattened, with distinctly broadened base, normally in pairs at base of leaves, mainly at base of stem with mixture of medium- sized heterogeneous prickles, prickles on very thin shoots (nearly) erect, often very thin; stipules rather broad, sometimes with glandular margin, with small, ovate divergent auricles, not increased in upper leaves; petioles short, slightly downy, sometimes glandular, with weak prickles; leaves 3— 10 cm long, leaflets 5—9, ovate, obovate, elliptic or oblong, the largest 1.5—4.5 cm long, 8—25 mm wide, obtuse, serrate-dentate, with simple teeth, grayish green, glabrous on both sides or slightly downy beneath, rather compact. Flowers few or rather numerous (at least on well-developed branches), in corymbs of 3—6, sometimes solitary; pedicels rather short, 0.5—1.6 cm long, smooth, often glandular -hispid, prickly; hypanthia ovoid, ellipsoid or oblong, usually smooth; sepals ovate or sublanceolate, with long, narrow appendage often broadened distally, entire, with slightly pubescent margins, laterally usually smooth, rarely slightly glandular -hispid; corolla (3)4—5 cm in diameter, pale pink or nearly white; disk two to three times as broad as hypanthium mouth; style head lanate; fruit globose or elliptic, 12— 18 mm in diameter, usually smooth, crowned by convergent, persistent sepals, on erect or drooping pedicels. June. (Plate XXVIII, Figure 5).
Steppe meadows, forest edges, banks of rivers and lakes.— W. Siberia: Irt.; Centr. Asia: Dzu.-Tarb., T. Sh., Pam.-Al. Gen. distr.: Mong., Dzu.-Kash. Described after cultivated specimen, probably from W.Siberia. Type unknown.
Economic importance. A good vitamin source; its fruit contains 4.15% ascorbic acid per dry weight of pulp.
Note. A polymorphic and probably composite species. The problematic R. kaschgarica Rupr. in Ost.-Sack. et Rupr. Sert. Tianshan (1869) 46, with its exceptionally large and robust prickles and coriaceous leaflets, described from the Suukta valley in Kashgar, is undoubtedly very close to this species; however, relevant material is so meager than we prefer not to treat it separately, the more so as it appears that it has never been collected in the USSR. It should also be compared with R.algoiensis Crep., described from Chinese Turkestan.

Book  (1956)  Page(s) 125.  
 
In "Breeding Of Hardy Roses," by Dr. F. L. Skinner:
...the true R. laxa Retzius...grows to a height of five to six feet here [Dropmore, Manitoba], and while the greatest flush of flowers is in late June it continues to bloom throughout the summer and both flowers and ripe fruit can usually be found on the bushes in September. It seems to be able to transmit this autumn flowering habit to many of its hybrids and also much more of its own hardiness than R. rugosa does to its hybrids. Rosa laxa has a peculiar scent and few people would call it fragrant, but when mated with some of the Spinosissima Hybrids it has given rise to some quite sweet scented roses.

Book  (1954)  Page(s) 155.  
 
First described in 1803; introduced in America by Dr. N.E. Hansen in 1913 from seed collected in Siberia.