LEGUMINOSAE. 13 
ACACIA, . 
(Family Leguminosae). 
Tender shrubs or small trees, 
usually with stipular spines or 
with strong prickles away from 
the nodes: more or less ever- 
green. Twigs slender, zig-zag, 
somewhat angular: pith small, 
roundish, continuous. Buds soli- 
tary, sessile, small, usually quick- 
ly developing into short spurs 
covered by leaves or their bases 
and sometimes bristling with 
pungent stipules, the end-bud 
lacking. Leaf-scars alternate, 
small, elliptical, somewhat raised: 
bundle-trace 1: stipules sometimes 
present as. strong sometimes 
greatly enlarged spines, which in 
many tropical species are inhab- 
ited by pugnacious ants. An ac- 
count of these (contributed by 
Safford) is to be found under the 
caption bull-horn in the Standard Cyclopedia of Horticulture. - 
Leaves, if present, bipinnate (in Australian species reduced 
to their dilated vertical petioles or phyllodia). 
1. 
2. 
3. 
Unarmed: stems very angular, hairy. A. filicina. 
Armed with pungent stipules or prickles. 2. 
Stipules strong and pungent. 3. 
Stipules weak: stems with strong hooked prickles. 4. 
Spines short or swollen. (1). A. Farnesiana. 
Spines becoming long (3-4 cm.) and slender. A. constricta. 
. Twigs brown: leafiets 3X10 mm. (2). A. Roemeriana. 
Twigs becoming gray: leaflets small (2X5 mm.). 
(Texas Mimosa). A. Greggii. 
