ile with a rounded base
=Rosin Weed, Silphium integrifolium.=

116c. Leaves tapering to a short petiole; principal leaves whorled
=Rosin Weed, Silphium trifoliatum.=

116d. Leaves abruptly rounded at the sessile base, all opposite
(Ox-eye) --117.

117a. Leaves smooth =Ox-eye, Heliopsis helianthoides.=

117b. Leaves rough =Ox-eye, Heliopsis scabra.=

118a. Principal stem-leaves lobed or divided --119.

118b. Principal stem-leaves entire or serrate --127.

119a. Submerged aquatic; leaf-segments filiform
=Water Marigold, Bidens beckii.=

119b. Terrestrial plants; leaves merely 3-lobed (3-8 dm. high; late
spring and summer) (Tickseed) --120.

119c. Terrestrial plants; leaves compound or dissected (summer and
autumn) --121.

120a. Leaf-lobes linear-oblong, all about equal
=Tickseed, Coreopsis palmata.=

120b. Lateral leaf-lobes very much smaller than the terminal
=Tickseed, Coreopsis lanceolata.=

121a. Leaf-segments entire (Tickseed) --122.

121b. Leaf-segments serrate (5-15 dm. high) (Tickseed Sunflower) --124.

122a. Leaf-segments numerous, linear or nearly so (4-10 dm. high)
--123.

122b. Leaf-segments 3-5, lanceolate (1-3 m. high)
=Tickseed, Coreopsis tripteris.=

123a. Rays yellow throughout =Tickseed, Coreopsis verticillata.=

123b. Rays brown, at least at the base =Tickseed, Coreopsis tinctoria.=

124a. Achenes wedge-shape, the inner ones less than 2 mm. wide
--125.

124b. Achenes obovate, the inner ones more than 2 mm. wide
=Tickseed Sunflower, Bidens aristosa.=

125a. Leaf-lobes lanceolate =Tickseed Sunflower, Bidens trichosperma.=

125b. Leaf-lobes linear
=Tickseed Sunflower, Bidens trichosperma var. tenuiloba.=

126a. Outer leaf-like bracts 10-16; achenes brown
=Beggar Ticks, Bidens vulgata.=

126b. Outer leaf-like bracts 5-8; achenes black
=Beggar Ticks, Bidens frondosa.=

126c. Outer leaf-like bracts about 4
=Beggar Ticks, Biden