12 Family Key 
BB. Twigs 6 mm. or less thick; leaves 7 cm. or less wide; inflorescence lateral and 
few-flowered, or flowers solitary in the leaf axils. 
C. Plant prostrate, creeping. Rubus in ROSACEAE (p. 206) 
CC. Plant erect or spreading. GROSSULARIACEAE (p. 204) 
AA. Leaves pinnately veined or |-veined. 
D. Spines few, very stout, 1.5—-5 cm. long; leaves serrate, ovate to obovate, 
25-=735.cem long, Crataegus in MALACEAE (p. 221) 
DD. Spines more slender, often shorter; leaves entire, usually narrower and shorter. 
E. Leaves 8—12 mm. long; petals white. Forsellesia in CELASTRACEAE (p. 248) 
EE. Leaves |2—37 mm. long; petals yellow or none. 
F. Flowers in heads; at least the young parts of the plant white-woolly; petals 
yellow. Tetradymia in COMPOSITACEAE (p. 372) 
FF. Flowers not in heads; young parts of the plant often mealy or pubescent 
but rarely white-woolly; petals yellow or none. 
G. Petals yellow, 10—15 mm. long; leaves sometimes lanceolate, mostly 
acicular and about 12 mm. long. Ulex in LEGUMINACEAE (p. 224) 
GG. Petals none; leaves linear to obovate, 12—-37 mm. long. 
CHENOPODIACEAE (p. 140) 
GROUP 7—Shrubs with alternate simple evergreen leaves and without spines or 
prickles on the branches 
A. Staminate flowers in aments; fruits in an ament-like cluster, or composed of a nut 
(acorn) in an involucral cup, or composed of 1—3 nuts in a very spiny involucral 
covering. 
B. Leaves oblanceolate, mostly serrate near the tip, not scurfy beneath; fruits in 
an ament-like cluster. MyrIcaAcEAE (p. 122) 
BB. Leaves either not oblanceolate, or else scurfy beneath and the margin entire. 
FAGACEAE (p. 124) 
AA. Flowers not in aments; fruit not as above. 
C. Petals none or distinct to the base. 
D. Sepals 3 or 6; petals 3 or none; leaves with only | chief vein from the base. 
E. Leaves not aromatic, linear-oblong, crowded, obtuse, 4—8 mm. long, rev- 
olute at margin; stamens 2—4; ovaries 2 to several; drupe 4—6 mm. long; 
plant 1—4.5 dm. high. EMPETRACEAE (p. 246) 
EE. Leaves very aromatic, lanceolate-oblong, acute, rounded to acute at base, 
5—10 cm. long, not revolute at margin; stamens 9; ovary |; drupe 20—25 
mm. long; plant 3—21 m. high. LAURACEAE (p. 173) 
DD. Sepals 4—5; petals 4—5 or none. 
F. Petals none; stamens 15—-25; fruit an akene, with a hairy tail 5—10 cm. 
long. Cercocarpus in ROSACEAE (p. 206) 
FF. Petals present; stamens 10 or fewer; fruit either fleshy or a capsule, not 
tailed. 
G. Leaves either densely woolly beneath, or with red hairs on the petiole and 
the veins beneath. Ledum in ERICACEAE (p. 294) 
GG. Leaves not woolly beneath, glabrous or nearly so. 
H. Shrub 7.5—30 cm. high; leaves sharply serrate; stamens 10; ovary 
5-celled. Chimaphila in PyROLACEAE (p. 291) 
HH. Shrub taller; leaves entire or serrulate; stamens 4—5; ovary 2—4- 
celled. RHAMNACEAE (p. 250) 
CC. Petals and sepals both present; petals more or less united into 1 piece. 
I. Ovary inferior; leaves oval to ovate, 2.5 cm. or less long, not densely crowded. 
VACCINIACEAE (p: 299) 
