193 
RUTA, rue 
¢Ruta graveolens L., common rue, p. 968 
ZANTHOXYLUM, prickly ash 
Zanthoxylum americanum Miller, common prickly ash, northern 
prickly ash, toothache tree, p. 966 
f. americanum 
SALICACEAE, willow family 
POPULUS, poplar 
pa 9" alba L., silver poplar, white poplar, p. 504 
alba 
1p. x Feil Moench, see named hybrid 
P. deltoides Bartram ex Marshall, Soaieee eastern cottonwood, 
southern cottonwood, p. 507 
*ssp. monilifera (Aiton) Eckenwalder (Eckenwalder, 1977a) 
ssp. deltoides [S: P. eras var. deltoides, incl. f. pilosa 
(S arg.) Sudw.; var. missouriensis (A. Henry) Rehder; 
M: P. deltoides| (Ecxenwaldet, 1977a, b) 
P. grandidentata Michaux, large-toothed aspen, p. 504 
P. heterophylla L., swamp cottonwood, 506 
+P. x jackii Sarg., see named _ 
+P. nigra L., black poplar, p. 507 
var. italica Muenchh. Lombardy poplar 
+P. tremula L., European aspen, p 
p. 5 
P. tremuloides Michaux, quaking aspen, trembling aspen, P- 506 
a ock 
S: Steyermark G: Great Plains Flora M: Mohlenbr 
