185 
PHYSOCARPUS, ninebark 
Physocarpus opulifolius (L.) Maxim., ninebark, p. 793 
var. intermedius (Rydb.) Robinson [M: P. opulifolius] 
(Robertson, 1974) 
POTENTILLA, cinquefoil 
*+Potentilla argentea L., silvery cinquefoil Sen lags 1979) 
. arguta Pursh, tall cinquefoil, prairie cinquefoil, p. 
P. canadensis L., Canada cinquefoil, five finger, p. bie 
var. villosissima Fern. 
P. nicolletii (S. Watson) E. Sheldon [G: P. paradoxa] (the validity 
of this weak segregate of P. paradoxa has not been 
examined critically), p. 830 
P. norvegica L., rough cinquefoil, Norwegian cinquefoil, p. 828 
P. paradoxa Nutt. ex Torrey & A. Gray, bushy cinquefoil, p. 830 
+P. recta L., rough-fruited cinquefoil, sulphur cinquefoil, p. 830 
P. rivalis Nutt. ex Torrey & A. Gray, brook cinquefoil, p. 828 
var. millegrana (Engelm. ex Lehm.) S. Watson [G: P. rivalis; M: 
P. millegrana Engelm. ex Lehm.] (the validity of this 
taxon has not been evaluated critically; see Robertson, 
1974) 
var. pentandra (Engelm.) S. Watson [G: P. rivalis] (the validity 
of this taxon has not been evaluated critically; see 
Robertson, 1974) 
var. rivalis 
- Simplex Michaux, common cinquefoil, old-field cinquefoil, five 
finger, p. 827 
var. argyrisma Fern. [G: P. simplex] (Robertson, 1974) 
var. calvescens Fern. [G: P. simplex] (Robertson, 1974) 
var. simplex 
a] 
PRUNUS, 
cherry, plum, peach, apricot 
Prunus americana Marshall, wild plum, p. 860 
P. angustifolia Marshall, Chickasaw plum, p. 861 
**P. armeniaca L., apricot (Miihlenberg, 1979) 
S: Steyermark G: Great Plains Flora M: Mohlenbrock 
