Family Key 
JJ. Not as above in all points. 
K. Plant parasitic on the branches of trees; leaves mere scales or normal, 
thick, mostly olive- or whitish-green. LORANTHACEAE (p. 128) 
KK. Plants not parasitic on the branches of trees; leaves various, usually 
normal. 
L. Plant densely hoary with stellate hairs, straight hairs also present; 
leaves ovate, entire, obtuse, at base cuneate or rounded, 1—5 cm. long. 
Piscaria in EUPHORBIACEAE (p. 245) 
Li. Plant not hoary with stellate pubescence; leaves mostly not fitting 
the above. 
M. Leaves in whorls of 3 or more, the whorls scattered along elon- 
gated stems. Group 10 (p. 15) 
MM. Leaves opposite or merely in a basal or a terminal whorl. 
N. Plants submerged or in water or in very wet places; leaves 
2 cm. or less long, entire; submerged leaves lanceolate or nar- 
rower; floating or emersed leaves linear to obovate; plant Chick- 
weed-like in appearance, slender, 5—-45 cm. high or long; ovary 
4-celled; styles 2. CALLITRICHACEAE (p. 246) 
NN. Plants not as above in all the vegetative characters. 
O. Stems prickly; flowers in heads; leaves 10—15 cm. long, 
lanceolate, sessile; flower-parts in 4’s. 
DIPSACACEAE (p. 368) 
OO. — Either stems not prickly or flowers not in heads. 
P. ‘Twining vines with palmately veined and lobed leaves. 
Humulus in MORACEAE (p. 126) 
PP. Not vines, or if so leaves not as above. 
Q. Corolla none or of separate petals. 
R. Ovary and fruit superior. Group I] (p. 15) 
RR. Ovary and fruit inferior, Group 12 (p. 17) 
QQ. Corolla of united petals. 
S. Plants with milky juice. 
T. Ovaries distinct but their styles and stigmas unit- 
ed, carpels later separating into 2 distinct fruits; 
stamens mostly monadelphous; pollen united into 
waxy masses. ASCLEPIADACEAE (p. 308) 
TT. Carpels quite distinct even in flowering; sta- 
mens distinct; pollen of simple grains. 
APOCYNACEAE (p. 308) 
SS. Plants without milky juice. Group 13 (p. 17) 
HH. Leaves alternate or all basal. 
U. Leaves compound. ; Group 14 (p. 18) 
UU. Leaves simple. 
V. Plants without green color; either white or yellow or red or brown. 
Group 15 (p. 19) 
VV. Plants with green color, altho also often wiih other colors present. 
W. Petals none, but calyx often petal-like. GrouP 16 (p. 20) 
WW. Petals present, distinct to base. 
X. Stamens many, at least more than 10 and twice as many as petals. 
Group 17 (p. 21) 
XX. Stamens 10 or fewer, or if more not exceeding twice the number 
of petals. Group 18 (p. 22) 
WWW. Petals present, more or less united. Group 19 (p. 23) 
