436 ROSACEAE 



15-30 mm. long; fruit convex, red, 15-20 mm. wide. Ruhits parviflorrts Nutt. 

 Riihus nutkanus Moc. Bossekia parviflora Greene. Open woods and among 

 bushes: Mich. — w Ont. — S.D. — N.M. — Calif. — s Alaska; n Mex. Submont. — 

 Mont. My-Jl. 



34. OREOBATUS Rydb. 



Prostrate or reclining or erect shrubs, with light-colored shreddy bark. 

 Leaves petioled, simple, maple- or gooseberry-like, digitately ribbed or lobed. 

 Flowers showy, usually solitary. Sepals 5, ovate or ovate-lanceolate, acuminate 

 or with fohaceous tips, in fruit erect. Petals white, pink, or purple, broadly 

 obovate. Stamens very numerous, in several series, hiding the rather few pistils. 

 Receptacle flat or nearly so. Styles club-shaped, densely pubescent, curved; 

 stigma somewhat 2-lobed. Drupelets rather few, fleshy, without hairj^ cushions. 



1. O. deliciosus (Torr.) Rydb. Stems mostly decumbent or prostrate, or 

 ascending; young branches almost velvety; leaf-blades reniform in outline, more 

 or less distinctly 3-7-lobed, 2-6 cm. broad; lobes very broad and rounded, den- 

 tate; flowers mostly solitary; sepals 10-15 mm. long, acuminate or with foli- 

 aceous tips; petals oval, white, 1.5-3 cm. long; fruit hemispheric, dark purple, 

 10-15 mm. broad. Ruh)is deliciosus Torr. Bossekia deliciosa A. Nels. Moim- 

 tains: Colo. Submont. — Mont. Je-S. 



35. RUBUS (Tourn.) L. Raspberry, Blackberry, Cloudberry. 



Perennial plants, ours either shrubs with biennial, prickly or bristly stems, 

 or herbaceous plants, with rootstocks or creeping stems, unarmed. Leaves al- 

 ternate, usually pinnately or pedately compound or rarely simple. Flowers 

 racemose, paniculate or rarely solitary, perfect, dioecious or polygamo-dioecious. 

 Hypanthium flat or saucer-shaped. Sepals 5, rarely 6-8, without bractlets. 

 Petals as many, deciduous. Stamens numerous, inserted on a disk at the margin 

 of the hypanthium. Pistils many, inserted on a convex or nipple-shaped, dry 

 or fleshy receptacle. Fruit of several or many fleshy drupelets. Ovules 2, col- 

 lateral, one abortive. 



Stem herbaceous, never prickly, rarely bristly; floral branches directly from the root- 

 stock or from stolons: stipules broad, free or nearly so. 

 Petals spreading or ascending; filaments not dilated. 



Plants dioecious ; drupelets many, coherent ; petals large and broad ; leaves merely 

 lobed. 1. R. Chamnernorus. 



Plants with perfect flowers; drupelets few, distinct; petals narrow; leaves pedately 

 5-foliolate. 2. R. pedatus. 



Petals erect; filaments dilated. 



Petals pink or rose-color; plants not stoloniferous ; floral branches directly from 

 the rootstock. 

 Petals oblanceolate or obovate, 10-1.5 mm. long, distinctly clawed; stem less 

 than 1 dm. high, usually 1-flowered; leaflets romided at the apex. 



3. R. ocaulis. 

 Petals broadly obovate, rounded or emarginate, scarcely clawed, 10 mm. long 

 or less; stem leafy, 1-3 dm. high, 1-5-flowered; stem-leaves with rhombic 

 acute leaflets. 4. R. arcticus. 



Petals wliite; plant stoloniferous. 



Plant wholly unarmed; flowers solitary or racemose. 5. R. pubesceT}S. 



Plant sparingly glandular-hispid above and sometimes with a few weak bristles; 



flowers corymbose. 6. R. transmonianus. 



Stem more or less woody, biennial oi perennial, usually prickly or bristly, if unarmed or 



merely bristly, then the stipules narrow and more or less adnate. 



Stipules broad, free or nearly so; stem decumbent, prickly. 7. R. nivalis. 



Stipules narrow, linear-lanceolate or subulate, adnate to the petioles. 



Carpels united into a thimble-shaped aggregate fruit, separating from the dry- 

 receptacle. 

 Flowers solitary or few; petals purplish, large, much exceeding the sepals; 



leaves green on both sides. 8. R- .ipeclabilis. 



Flowers clustered; petals white, usually shorter than the sepals; leaves more.! 

 or less tomentose or at least glaucous beneath. f 



Inflore.scence corymbiform; fruit black or purple; stem piickly; leaves,! 

 when having more than 3 leaflets, pedately compound. 

 Prickles of the inflorescence not flattened, straightish; leaflets dark] 

 green above, acuminate, with small teeth; stem usually dark bluish, 

 with a bloom. 9. R. occidentalis. 



Prickles of the inflorescence strongly flattened and ciuved; leaflets 

 yellowish green above, acute, with coarse teeth; branches usually 

 straw-colored. 10. R. leucodermis. 



