KEY TO THE FAMILIES 
19 
Stamens and pistils in different flowers; flower-clusters often surrounded 
by a petal-like involucre so that they resemble a single flower. 
Euphorbiaceae, p. 65. 
b. Calyx present, green or often corolla-like; corolla wanting. 
Stipules present. 
Stipules sheathing, scarious; calyx 5 to 6-parted, or of distinct petals, 
often petal-like; stamens 4 to 9. Polygonaceae, p. 55. 
Stipules not sheathing; calyx greenish; stamens 1 to 4. 
Ovule pendulous; styles or stigmas 2.Cannabaceae, p. 62. 
Ovule erect; style and stigma 1. Urticaceae, p. 61. 
Stipules none. 
Pistils more than 1 and distinct. Ranunculaceae, p. 30. 
Pistil only 1. 
Fruit an achene or utricle; ovary 1-celled. 
Leaves opposite or whorled. 
Calyx of 6 or 5 distinct or nearly distinct petal-like 
sepals ; stamens 4 to 9. Polygonaceae, p. 55. 
Calyx tubular, its base forming a hardened covering to 
the achene; stamens 3 to 5... 
Nyctaginaceae, p. 50. 
Leaves alternate or opposite. 
Sepals herbaceous or, in unisexual flowers, the-pistil¬ 
late without calyx and enclosed by 2 bracts; 
bractlets none. Chenopodiaceae, p. 48. 
Sepals membranous or scarious; flowers with bractlets... 
Amaranthaceae, p. 47. 
Fruit a capsule. 
Ovary inferior. 
Leaves opposite or whorled; ovary 1 to 12-celled. 
Aizo'aceae, p. 51. 
Leaves basal, reniform or cordate; ovary 6-celled; 
calyx-lobes 3, caudate. Asarum, p. 60. 
Ovary superior, 3 or 1-celled. Euphorbiaceae, p. 65. 
II. CHORIPETALOUS DIVISION. Calyx and corolla pres¬ 
ent; petals distinct or nearly so, or merely connivent. 
A. Stamens hypogynous (on the receptacle below the superior ovary, or 
sometimes on the base of the petals). 
1. Stamens more than 10. 
Stamens monadelphous; pistils cohering in a ring around a central axis, 
or pistil 1 and more than 1-celled. Malvaceae, p. 78. 
Stamens distinct; all herbs or herb-like except one genus in Papaveraceae. 
Pistils more than 1 and distinct, becoming follicles or achenes, rarely 
a berry. Ranunculaceae, p. 30. 
