17b. Leaves narrowly lanceolate, not revolute (2-4 dm. high) =Willow Herb, Epilobium pal.u.s.tre.=

18a. Seeds tipped with a tuft of reddish-brown hairs =Willow Herb, Epilobium coloratum.=

18b. Seeds tipped with a tuft of white hairs =Willow Herb, Epilobium adenocaulon.=

HALORAGIDACEAE, the Water Milfoil Family

Aquatic or marsh herbs, with alternate, opposite, or whorled leaves, and small, inconspicuous terminal or axillary flowers, frequently without petals (summer).

1a. Leaves none, or else very small and inconspicuous =Water Milfoil, Myriophyllum tenellum.=

1b. Leaves alternate (1-4 dm. high) =Mermaid Weed, Proserpinaca pal.u.s.tris.=

1c. Leaves opposite or whorled --2.

2a. Leaves entire (2-4 dm. high) =Mare's-tail, Hippuris vulgaris.=

2b. Leaves toothed or dissected (Water Milfoil) --3.

3a. Flowers in the axils of foliage leaves --4.

3b. Flowers in terminal spikes, subtended by bracts --5.

4a. Flowers above water, subtended by toothed or entire leaves =Water Milfoil, Myriophyllum heterophyllum.=

4b. Flowers submerged, subtended by dissected leaves =Water Milfoil, Myriophyllum farwellii.=

5a. Flowers solitary or in pairs at each joint of the spike =Water Milfoil, Myriophyllum alternifolium.=

5b. Flowers several at each joint of the spike --6.

6a. Bracts deeply pinnatifid =Water Milfoil, Myriophyllum verticillatum var. pectinatum.=

6b. Bracts entire or toothed =Water Milfoil, Myriophyllum spicatum.=

ARALIACEAE, the Sarsaparilla Family

Herbs or th.o.r.n.y shrubs, with alternate or whorled leaves, and small flowers in umbels; sepals 5, minute; petals and stamens each 5; ovary inferior, with 2-5 styles, ripening into a berry.

1a. Leaves simple, palmately lobed (th.o.r.n.y shrub; flowers greenish-white, in panicles, in June) =Devil's Club, Fatsia horrida.=

1b. Leaves once compounded, whorled (umbel one, terminal) --2.

1c. Leaves twice or thrice compounded (umbels several) --3.

2a. Leaflets sessile; flowers white, in spring (1-2 dm. high) =Dwarf Ginseng, Panax trifolium.=

2b. Leaflets stalked; flowers greenish, in summer (2-5 dm. high) =Ginseng, Panax quinquefolium.=

3a. Stem and petioles spiny or bristly (flowers white, summer) --4.

3b. Stem and petioles smooth or a little p.u.b.escent (flowers greenish-white) --5.

4a. Shrubby, with stout thorns (1-3 m. high) =Hercules' Club, Aralia spinosa.=

4b. Herbaceous, with slender bristles (4-10 dm. high) =Bristly Sarsaparilla, Aralia hispida.=

5a. Stem-leaves present; leaflets cordate at the base (8-15 dm. high; summer) =Spikenard, Aralia racemosa.=

5b. Leaf and flower-stalk arising from the ground; leaflets acute at the base (2-4 dm. high; spring) =Wild Sarsaparilla, Aralia nudicaulis.=

UMBELLIFERAE, the Parsley Family

Herbs, with alternate, usually compound leaves, the petioles dilated at the base; flowers small, in umbels or heads; sepals 5, minute or even wanting; petals and stamens each 5; ovary inferior, with 2 styles, ripening into a dry fruit.

1a. Leaves simple (flowers in summer) --2.

1b. Leaves compound, or at least deeply cleft --4.

2a. Leaves linear, sword-shape (4-10 dm. tall; flowers greenish-white) =Rattlesnake Master, Eryngium yuccifolium.=

2b. Leaves kidney-shape or almost circular (stems creeping, about 1 dm. high; flowers white) (Water Pennywort) --3.

3a. Leaves peltate, attached by the center =Water Pennywort, Hydrocotyle umbellata.=

3b. Leaves not peltate, attached by the margin =Water Pennywort, Hydrocotyle americana.=

4a. Flowers yellow or purple --5.

4b. Flowers white or greenish --13.

5a. Leaf-segments entire (4-8 dm. high) --6.

5b. Leaf-segments toothed or incised --7.

6a. Leaf-segments filiform (summer) =Fennel, Foeniculum vulgare.=