ROSACEAE (ROSE FAMILY) 495 



pistils below. Ovaries hairy, becoming bony achenes in fruit. Shrubs, usually 

 prickly, with odd-pinnate leaves, and stipules adnate to the petiole ; stalks, foli- 

 age, etc., often bearing aromatic glands. Many of the species highly variable 

 and often indeterminable from imperfect specimens. (The ancient Latin name.) 



a. Styles coherent in a protruding column, as long as the stamens . . 1. JR. setigera. 

 a. Styles distinct b. 



b. Sepals connivent after flowering, persistent ; pedicels and receptacle 



naked c. 



c. Prickles scattered or none, the infra-stipular when present not en- 

 larged. 



Leaf-rhachis glandular-puberulent or -bristly. 



Fruit pyriforrn, obovoid or oblong, top-shaped at base . 2. R. adcularis. 



Fruit subglobose, obtuse or rounded at base (2) R. acicularis, v. Hourgeauiana. 

 Leaf-rhachis softly and finely villous or tomentulose ; glandular 

 hairs merely occasional or none. 



Prickles numerous, scattered ; leaflets 7-11 8. R. pratincola. 



Prickles occasionally present on main stem but mostly few or 



none; leaflets 5-7 4. R.blanda. 



c. Prickles not wholly uniform, the infra-stipular somewhat stouter. 

 Calyx-lobes essentially entire. 

 Calyx-lobes 1-1.5 cm. long. 

 Leaves 6-10 cm. long ; leaflets pubescent beneath ; stem armed 



chiefly near the nodes 5. R. Woodsii. 



Leaves 2-4 cm. long ; leaflets essentially glabrous ; stem ex- 

 cessively spiny throughout 6. R. spinosissima. 



Calyx-lobes 2-2.5 cm. long 7. R. cinnamomea. 



Outer calyx-lobes conspicuously pinnatifid 8. R. canina. 



6. Sepals spreading after flowering, deciduous from the mature fruit ; 



receptacle and pedicels more or less hispid or tomentose. 



Leaflets thick, evergreen or nearly so ; receptacle tomentose . 9. R. bracteata. 



Leaflets membranaceous ; receptacle not tomentose. 

 Leaf-rhachis very glandular. 



Prickles strong, hooked ; leaflets rarely 2 cm. long . . .10. R. rubiginosa. 

 Prickles weak, acicular, often gland-tipped ; leaflets 8-6 cm. 



long 11. .R. gallica. 



Leaf-rhachis puberulent or glabrous, scarcely if at all glandular. 

 Young growth densely covered, even into the inflorescence, 



with needle-like prickles 12. R. nitida. 



Young growth armed at the nodes or not at all. 

 Stipules narrowly linear, their free auricles merely short- 

 lanceolate teeth ; leaflets serrulate ; infra-stipular prickles 

 short, 2-4 (rarely 6) mm. long, broad-based and decidedly 



curved 13. R. cwoUna. 



Stipules more dilated, oblanceolate, their auricles somewhat 

 deltoid ; serratures of the leaflets coarser and deeper ; 

 infra-stipular prickles longer. 



Prickles decidedly curved ; leaflets somewhat shining above 14. R. virginiana. 

 Prickles straight or nearly so ; leaflets dull above . . 15. R. humilis. 



1. R. setigera Michx. (CLIMBING or PRAIRIE R.) Stems climbing, armed 

 with stout nearly straight scattered prickles, not bristly ; leaflets 3-5, ovate, 

 acute, sharply serrate, smooth or downy beneath ; stalks and calyx glandular ; 

 flowers corymbed ; sepals pointed ; petals deep rose-color changing to white ; 

 fruit globular. Borders of prairies and thickets, Ont. to Fla., w. to Wise., Neb., 

 and Tex.; also an escape from cultivation in Ct. July. Strong shoots growing 

 3-6 m. in a season. 



2. R. acicularis Lindl. Stems 3-12 dm. high, very prickly ; stipules usually 

 dilated, glandular-ciliate and resinous ; leaflets 3-7, broadly elliptical to oblong- 

 lanceolate, sessile and obtuse or subcordate at base, usually pale and somewhat 

 resinous-puberulent beneath, the teeth serrulate; flowers large, solitary (very 

 rarely 2-3) ; outer sepals usually with 1-2 narrow lateral lobes, not hispid ; fmit 

 obovoid or ellipsoid, top-shaped at base. (J?. Engelmanni Wats.) Sandy 

 thickets, L. Huron to Minn., Col., and Ida. (Siber.) 



Var. Bourgeauiana Crepin. Fruit globose, rounded at base ; leaves some- 

 times smoothish but more often soft-pubescent and resinous-pulverulent beneath. 

 Ledges, rocky woods, etc., Anticosti to s. Vt.,.n. Mich., centr. 111., Col., and 

 northw. 



3. R. pratincola Greene. Stems low, very prickly ; stipules narrow, more or 

 less glandular-toothed above (or even glandular-ciliate) ; leaflets 7-11, broadly 

 elliptical to oblong-oblanceolate, subcuneate at base, somewhat firm and strongly 



