BROOKLYN BOTANIC GARDEN 
LEAFLETS 
Series VII Brooklyn, N. Y., May 21, 1919 
No. 5 
KEY TO SOME OF THE PRINCIPAL 
FAMILIES OF FLOWERING PLANTS 
I. Dicotyledons, with 2 seed-leaves (100,000 species). Flowersgen- 
erally in 5s or 4s; leaves netted-veined; fibro-vascular bundles 
arranged in a circle. 
1. Petals none (Apetalous); with or without calyx. Mostly wind 
pollinated. 
2. Flowers in scaly spikes, or catkins. Trees or shrubs. 
3. The two sexes on different plants (dioecious) — Salicaceae 
(Willow, Poplar). 
3. The two sexes on the same plant (monoecious). 
4. Leaves pinnately compound (Juglandaceae) (Walnut, 
Hickory) . 
4. Leaves simple. 
5. Pistillate flowers in catkins — Betulaceae (Birch, Alder, 
Hazel, Hornbeam). 
5. Pistillate flower form nuts, enclosed in bracts ( cupules) 
— Fagaceae (Beech, Chestnut, Oak). 
5. Pistillate flowers form fleshy fruit— Moraceae (Mulberry, 
Osage Orange, Fig, Breadfruit). 
2. Flowers not in catkins Calyx sometimes petal-like. 
3. Shrubs or trees — Elm, Hackberry, Maple (sometimes with 
petals); Sycamore, Sassafras, Camphor, Cinnamon, 
Leatherwood. 
3. Herbs. 
4. Pistil 1. 
5. Stipules sheathing the stem at swollen joints— Polygon- 
accae. (Buckwheat, Rhubarb, Smartweed, Dock). 
5. Weedy herbs. Flowers small, greenish— Chenopodiaceae 
(Lamb’s quarters, Beet, Chard, Spinach). 
5. Weedy herbs. Flowers scarious— Amaranthaceae (Pig- 
weed, or Amaranth family). 
5. Calyx tubular or funnel-form, and colored like a 
corolla— Nyctaginaceae (Four-o’clock family). 
5. With milky juice and reduced flowers— Euphorbiaceae 
(Spurge family) (Castor bean, Hevea — Brazilian rub- 
ber tree, Poinsettia, Crown-of-Thorns ). 
4. Pistils generally more than 1. Stamens numerous, on 
the receptacle. Petals sometimes present — Ranuncula- 
ceae (Crowfoot family) (Anemone, Marsh Marigold) . 
