211 
ULMACEAE, elm family 
CELTIS, hackberry 
Celtis laevigata Willd., sugarberry, southern hackberry, p. 559 
var. laevigata 
var. smallii (Beadle) Sarg. 
var. texana Sarg. 
occidentalis L., northern hackberry, nettle tree, p. 558 
var. canina (Raf.) Sarg. 
var. occidentalis 
var. pumila (Pursh) A. Gray 
. tenuifolia Nutt., dwarf hackberry, p. 559 
var. georgiana (Small) Fern. & B. G. Schubert [G: C. 
tenuifolia] (the validity of varieties in this and other 
Celtis species is suspect; see Wagner (1974) for 
discussion) 
var. tenuifolia 
‘s) 
Q 
PLANERA, water elm, planer tree 
Planera aquatica (Walter) J. Gmelin, p. 556 
ULMUS, elm 
Ulmus alata Michaux, winged elm, wahoo, P- 555 
U. americana L., American elm, white elm, p- 554 
*U. crassifolia Nutt., cedar elm (Heineke, 1987) 
*U. pumila L., Siberian elm, dwarf elm, p. 55° 
U. rubra Muhlenb., slippery elm, p. 555 
U. thomasii Sarg., rock elm, cork elm, p. 594 
UMBELLIFERAE (see APIACEAE) 
° brock 
S: Steyermark G: Great Plains Flora M: Mohlen 
