=Hackberry, Celtis occidentalis.=

4a. Some of the branches with flat corky wings; leaves smooth above
=Cork Elm, Ulmus racemosa.=

4b. Branches without corky wings; leaves more or less rough above
--5.

5a. Petioles and axillary buds glabrous =White Elm, Ulmus americana.=

5b. Petioles and axillary buds pubescent with rusty hairs
=Slippery Elm, Ulmus fulva.=

6a. Leaves rough above =Red Mulberry, Morus rubra.=

6b. Leaves smooth above =White Mulberry, Morus alba.=

7a. Leaves alternate --8.

7b. Leaves opposite --9.

8a. Leaves 2-5 cm. long, stems pubescent
=Pellitory, Parietaria pennsylvanica.=

8b. Leaves 8-20 cm. long; stem armed with stinging hairs
=Wood Nettle, Laportea canadensis.=

9a. Twining plant; leaves serrate or cleft =Hop, Humulus lupulus.=

9b. Erect plant; leaves palmately compound =Hemp, Cannabis sativa.=

9c. Erect plants; leaves not lobed or compound --10.

10a. Stems armed with stinging hairs --11.

10b. Stems glabrous or rough, but not with stinging hairs --12.

11a. Leaves ovate, with a heart-shape base
=Stinging Nettle, Urtica dioica.=

11b. Leaves lanceolate or ovate-lanceolate, not heart-shape at base
=Slender Nettle, Urtica gracilis.=

12a. Stems glabrous, pellucid
=Clearweed, Pilea pumila.=

12b. Stems rough, opaque =False Nettle, Boehmeria cylindrica.=

SANTALACEAE, the Sandalwood Family

Low herbs with alternate entire leaves and terminal clusters of small
greenish-white bell-shape flowers without petals in spring and early
summer.

1a. Inflorescence of several-flowered clusters terminating the stem and
in the upper axils =Toad-flax, Comandra umbellata.=

1b. Inflorescence of axillary clusters of 1-5 flowers
=Toad-flax, Comandra livida.=

LORANTHACEAE, the Mistletoe Family

Parasitic plants, attached to the branches of trees.

One species in Michigan, a dwarf brown plant 5-20 mm. long, with minute
scale-like leaves, growing on the branches of Black Spruce