458 



ROSACEAE 



dioecious, staminate large with elongated petals, pistillate small with broad petals ; fruit per- 

 sistent on the receptacle, oblong, black and sweet, glabrous or nearly so. 



Stream banks and open woods especially in burned areas, mainly Humid Transition Zone; British Columbia 

 and Idaho south along the coast to San Francisco, California. Type locality: San Francisco, California. March- 

 Aug. 



Rubus vitifolius subsp. ursinus (Cham. & Sch.) Abrams. (Rubus ursinus Cham. & Sch. Linnaea 2: 11. 

 1827. Rubus Menziesii Hook. Fl. Bor. Amer. 1: 179. 1832. Rubus Eastwoodianus Rydb. N. Amer. Fl. 22: 

 460. 1913.) Distinguished from the typical form chiefly by the more pubescent leaves which are more or less 

 densely soft-pubescent and canescent on the lower surface. This subspecies replaces the typical species throughout 

 California except along the northern coast, extending south to northern Lower California, mainly Upper Sonoran 

 Zone. Type locality : San Francisco, California. 



10. Rubus laciniatus Willd. Evergreen or Cutleaved Blackberry. Fig. 2501. 



Rubus laciniatus Willd. Hort. Berol. pi. 82. 1807. 



Rubus vulgaris var. laciniatus Dippel, Hanb, Laubh. Deuts, Dendr. Ges. 3: 529. 1893. 



Stems woody, perennial, climbing, 3-5 m. long, armed with numerous stout recurved 

 prickles. Leaves 5-foliolate, or those of the floral branches 1-3-foliolate; leaflets pinnately cleft 

 or parted and laciniately incised, sparsely pubescent beneath ; petioles prickly ; flowers in cor- 

 ymbs; sepals pubescent and prickly; petals white or pinkish, often incisely cleft; fruit black, 

 globose, 12-15 mm. in diameter. 



An escape from cultivation and becoming naturalized, especially in western Washington and Oregon. Type 

 locality: unknown. May- Aug. 



31. ROSA [Tourn.] L. Sp. PI. 491. 1753. 



Prickly shrubs with odd-pinnate leaves, adnate stipules and large solitary or corymbose 

 flowers. Hypanthium globose or urceolate. Bractlets none. Sepals 5. Petals 5, rounded, 

 spreading. Stamens many on the silky disk, which lines the hypanthium. Pistils many, 

 included in the hypanthium, but free and distinct; styles subterminal; ovules solitary, 

 pendulous. Achene bony, enclosed in the fleshy, enlarged, red, berry-like hypanthium. 

 [The ancient Latin name of the rose.] 



A genus of approximately 125 species, natives of the northern hemisphere. Type species, Rosa centifolia L. 



Pistils numerous; styles and upper part of hypanthium persistent in fruit. 



Sepals spreading or reflexed in fruit and tardily deciduous; leaves glandular-pruinose beneath and sweet- 

 scented. 1. R. rubiginosa. 

 Sepals erect and persistent in fruit; leaves scarcely or not at all sweet-scented. 



Flowers mostly solitary; petals normally over 2 cm. long; leaflets glabrous above; fruit 12-20 mm. thick. 

 Pedicels and calyx not bristly. 

 Leaflets double-toothed. 



Prickles straight or nearly so. 



Prickles stout, more or less flattened below; petioles not pilose. 

 Prickles slender, nearly terete; petioles distinctly pilose. 

 Prickles strongly curved. 

 Leaflets simple-toothed. 

 Pedicels and sepals densely bristly; hypanthium densely bristly. 

 Flowers mostly corymbose, if solitary petals less than 2 cm. long; fruit usually less than 10 mm. thick. 

 Hypanthium smooth or rarely pilose. 

 Leaves pubescent or puberulent. 



Rachis and leaflets more or less pubescent and often glandular. 



Leaflets double-toothed, the teeth, lower surface of leaflets and rachis distinctly 



glandular. 7. R. Aldersonii. 



Leaflets mostly simple-toothed, the lower surface and rachis scarcely glandular. 



8. R. calif ornica. 

 Rachis and lower surface of leaflets finely puberulent, not glandular. 



Leaflets elliptical to oval, nearly equally green on both surfaces. 



Sepals glandular-hispid on the back. 9. R. pisocarpa. 

 Sepals not glandular-hispid. 



Stems sparsely prickly; leaflets firm. 10. R. ultramontana. 



Stems densely prickly; leaflets thin. 11. R. gratissima. 



Leaflets obovate, pale and more or less glaucous beneath. 12. R. Macounii. 

 Leaves glabrous throughout. 



Leaflets broadly oval, 3-5 cm. long. 13. R. rivalis. 



Leaflets elliptic, rarely 3 cm. long. 14. 7?. mohavensis. 

 Hypanthium densely glandular -hispid. 



Leaflets rather thin and green, not glaucous. 15. R. spithamaea. 



Leaflets firm and distinctly glaucous. 16. R. sonomensis. 

 Pistils few; styles and upper part of hypanthium deciduous in fruit. 



Leaflets glabrous beneath. 17. 



Leaflets pubescent beneath. 18. 



1. Rosa rubiginosa L. Sweetbrier. Fig. 2502. 



Rosa rubiginosa L. Mant. 2: 564. 1771. 



Rosa micrantha Borrer ex Smith, Engl. Bot. pi. 2490. 1813. 



Rosa suaveolens Pursh, Fl. Amer. Sept. 346. 1814. 



Rosa Walpoleana Greene, Leaflets Bot. Obs. 2: 264. 1912. 



Stems branched, 1.5-2.5 m. high, often forming long wands, armed with stout flat recurved 



R. gymnocarpa. 

 R. Bridgesii. 



