The Manual of the Botany of the Northern United States / Including the District East of the Mississippi and North of North Carolina and Tennessee

by Asa Gray

[+] Seeds and ovules 2 in each cell; flowers monœcious.

2. Pachysandra. Flowers in basal spikes. Calyx 4-parted. Stamens 4, distinct.

3. Phyllanthus. Flowers axillary. Stamens 3, united.

[+][+] Seeds and ovules 1 in each cell.

a. Flowers apetalous, in cymose panicles (2–3-chotomous); stamens 10, erect in the bud.

4. Jatropha. Calyx corolla-like, the staminate salver-form; armed with stinging hairs.

b. Flowers in terminal racemes or spikes. Stamens inflexed in the bud. Stellate-downy or scurfy, or hairy and glandular; leaves mostly entire.

5. Croton. Flowers spiked or glomerate. Ovary and fruit 3- (rarely 2–4-) celled.

6. Crotonopsis. Flowers scattered on the branchlets. Ovary and fruit 1-celled.

c. Flowers in axillary spikes or racemes (except n. 9), apetalous (except n. 7). Stamens 8 or more; anthers erect in the bud.