Family Key 15 
GG. Ovary inferior or mainly so. 
J. Flowers in terminal cymes; stamens 3; leaves 3—5-foliolate. 
Valeriana in VALERIANACEAE (p. 367) 
JJ. Flowers in heads; stamens 4—5; leaves various. 
COMPOSITACEAE (p. 372) 
GROUP 10—Dicotyledonous herbs with simple leaves in whorls of 3 or more scattered 
along the stem 
A. Stem square; leaves 4—8 in a whorl; fruit very deeply 2-lobed or separating into 
2 distinct carpels. Galium in RUBIACEAE (p. 363) 
AA. Either the stem terete or else the leaves in whorls of 2—3; fruit not deeply lobed, 
not separating into distinct carpels. 
B. Plants growing in water; stem simple; stamen |. 
Hippuris in HALORAGIDACEAE (p. 269) 
BB. Plants of ordinary dry soil; stem normally not simple; stamens 2—10 or in 
Euphorbia only 1). 
C. Leaves terete, 8—16 in a whorl; styles 5. 
Spergula in CARYOPHYLLACEAE (p. 152) 
CC. Leaves flat, 2—6 in a whorl; styles | or 3. 
D. Leaves 4—6 in a whorl, 2.5 cm. or less long, spatulate or oblanceolate; 
stems prostrate; styles 3. AIZOACEAE (p. 147) 
DD. Leaves 2—4 in a whorl, often longer, blade often widest below its mid- 
dle; stems not prostrate (except sometimes in Euphorbia). 
E. Sepals 2—3, distinct; petals 4 or 6, distinct. 
Platystigma in PAPAVERACEAE (p. 173) 
EE. Sepals either none or 4—8 and all somewhat united into | piece; petals 
none or united into | piece. 
F. Corolla present; stamens 4—8. 
G. Leaves in several whorls along an elongated stem. 
SCROPHULARIACEAE (p. 341) 
GG. Leaves either not in whorls or the whorls merely basal or ter- 

minal. PRIMULACEAE (p. 300) 
FF. Corolla none; stamens | or 2 or 3 or 9. 
H. Calyx present; stamens more than |; fruit an akene, 3-angled. 
POLYGONACEAE (p. 130) 
HH. Calyx none; stamen |; fruit a capsule, 3-celled, terete or nearly 
sO. Euphorbia in EUPHORBIACEAE (p. 245) 
GROUP 11—Apetalous or polypetalous dicotyledonous herbs with opposite simple 
leaves and superior ovary 
A. Petals none. 
B. Leaves 2—3-pinnatifid; leaf segments linear to lanceolate; pistils more than 1; 
fruit akenes with plumose tails 2.5—-3.7 cm. long. 
Clematis in RANUNCULACEAE (p. 162) 
BB. Leaves not dissected; pistil 1; fruit without plumose tail. 
C. Plants with milky juice. Euphorbia in EUPHORBIACEAE (p. 245) 
CC. Plants without milky juice. 
D. Plants with stinging hairs; stems mostly simple, erect, 4-angled, 6—2] 
dm. high. Urtica in URTICACEAE (p. 127) 
DD. Plants without stinging hairs; stems not as above in all points. 
E. Seeds several to many. 
