Light-pink to deep-rose colored floivers are borne on lateral shoots from old wood, 

 which are usually over 10 cm long. Flowers are rarely solitary, usually there are four 

 or more in a corvmbiform cyme. The five persistent sepals are from 1 to 2 cm long, 2 

 to 3.5 mm wide at base. The tip of each sepal is usually a little expanded above the 

 median constriction. The sepals are erect or spreading in fruit. Woods rose petals 

 are five in number and 1.0 to 2.5 cm long. Stamens and pistils are numerous. The 

 capitate stigmas form a cluster closing the mouth of the hypanthium. Blooming occurs 

 from late spring through midsummer, varying considerably according to elevation and 

 exposure . 



The fleshy globose to ellipsoid fruit [hip) (fig- 40) is 6 to 15 mm wide and up 

 to 2.0 cm long and contains 15 to 30 achenes. Each achene is 3 to 4 mm long with stiff 

 hairs along one side. Wood rose averages 45,300 cleaned seeds per pound (100/g) 

 (Plummer and others 1968) . 



Woods rose exhibits much variation in growth habit, number of prickles, vegetative 

 spread, and drought tolerance. Some authorities, among them Hitchock and others (1961), 

 recognize two varieties. Under this treatment, variety ultramontana is the prevalent 

 one in the Intermountain area. Variety woodsii is the common woods rose on the plains 

 and prairie east of the Rocky Mountains. Even within varieties there is substantial 

 variation . 



Hybridization: The genus Rosa is a natural plant assemblage. Its species, how- 

 ever, are often difficult to distinguish (Erlanson 1934; Harrington 1954). Many of the 

 wild roses of western North America hybridize (Hitchcock and others 1961) . Improved 

 stock for planting purposes could be obtained by selection and breeding of the richly 

 variable woods rose and its relatives. 



The chromosome number of woods rose is 2n = 14 (Hitchcock and others 1961) . 



Distribution and Habitat: Woods rose is widely distributed in western Canada and 

 the western United States. It is found from valley floors to alpine sites, 1,070 to 

 3,320 m (3,500 to 11,000 feet). It is most abundant in such moist places as along stream 

 banks, but is also found in relatively dry habitats on mountain ranges. It flourishes 

 in moderate shade to full sunlight and so makes good growth on all aspects. Woods rose 

 is seldom found where the average annual precipitation is less than 260 mm (12 inches) . 



Use: Woods rose is browsed in all seasons by livestock and big game; however, 

 heaviest use is in the early spring and in the fall. Forms having few or no prickles 

 are generally preferred, but a high density of prickles has a survival value, preserv- 

 ing plants from being too heavily grazed. Even the heavily prickled populations some- 

 times receive substantial use. The persistent hips provide food for birds and upland 

 game species in the winter when little other food is available. 



Some ecotypes of woods rose spread aggressively by root sprouting. These are 

 excellent for soil stabilization. It is readily established on roadcuts and fills from 

 both nursery stock and wildings. Results from direct seeding have been variable but, 

 no doubt J can be improved. 



Accessory fruit formed by the fleshy calyx enclosing the true fruits, the 



achenes . 



32 



