POLYPETALOUS EXOGENOUS PLANTS. 2o5 



petals 5, deciduous ; stamens numerous ; achenia juicy, 

 crowded on the conical or cylindrical receptacle; style 

 nearly terminal, deciduous. — Perennial or sliruhhy and 

 nearly prickly plants, with lobed or compound petioled 

 leavesy and white or reddish /ozrcrs. 



* Heads of achenia oval or oUong, persistent ; receptacle juicy. 



R. viLLOSUS, Ait. Stern erect or bending, tall, shrubby, 

 armed like petioles and peduncles with stout recurved 

 prickles, the branches and 3-7-foliolate leaves soft-hairy 

 or nearly smooth; leaflets ovate or oblong, doubly serrate; 

 racemes leafy below, bracted above; sejmls acuminate, 

 much shorter than the obovate white petals ; fruit large, 

 oblong, black. Stem 4°-10° high. 



R. TRiviALis, Michx. Shruhhy, and armed with stout, 

 straight, or recurved prickles and bristly hairs ; stem pros- 

 trate, slender; leaves 3-5-foliolate, partly persistent; leaf- 

 lets smooth, oblong ovate or obovate, acute, sharply ser- 

 rate; racemes few-flowered, leafy below, mostly longer 

 than the leaves ; flowers large, white ; f7'uit black. 



R. HISPIDUS, L. Somewhat shruhhy, and armed with 

 weak bristle-like prickles; stem slender, prostrate; leaves 

 trifoliolate, persistent ; leaflets obovate, obtuse, coarsely 

 serrate, smooth ; racemes many-flowered, slender, longer 

 than the leaves ; floivers small, white ; fruit of few large 

 and black achenia. Fruit sour. 



ROSA, Tourn. Rose. 



Calyx 5-cleft, the urn-shaped tube becoming fleshy in 

 fruit; petals 5 ; stamens numerous, inserted with the petals 

 on the throat of the calyx ; ovaries numerous, hairy, in- 

 serted on the thin receptacle that lines the inner surface 

 of the calyx-tube ; styles nearly included ; achenia bony. — 



