Bitter Dogbane, Flytrap Dogbane, Spreading Dogbane: Apocynum androsaemifolium var. androsaemifolium (Synonyms: Apocynum androsaemifolium ssp. androsaemifolium, Apocynum androsaemifolium var. incanum) - Flowers pink and 5-7 mm long. Plants 20-50 cm high. Calyx less than half as long as the corolla. Leaves oval, petiolate and spreading or drooping. Corolla bell-shaped with narrow sepals.
Dwarf Dogbane, Flytrap Dogbane: Apocynum androsaemifolium var. pumilum (Synonyms: Apocynum androsaemifolium ssp. pumilum, Apocnum androsaemifolium var. pumilum, Apocynum androsaemifolium var. tomentellum, Apocynum pumilum, Apocynum pumilum var. pumilum, Apocynum pumilum var. rhomboideum) - lowers pink and 5-7 mm long. Plants 20-50 cm high. Calyx less than half as long as the corolla. Leaves oval, petiolate and spreading or drooping. Corolla tubular with broadly triangular sepals.
Common Dogbane, Hemp Dogbane, Indian-hemp: Apocynum cannabinum (Synonyms: Apocynum cannabinum var. glaberrimum, Apocynum cannabinum var. suksdorfii, Apocynum sibiricum) - Flowers white to greenish-white and 2-4 mm long. Plants 30-100 cm high. Leaves short petiolate above, often subsessile below.
Western Dogbane: Apocynum X floribundum (Synonyms: Apocynum medium, Apocynum medium var. floribundum, Apocynum medium var. lividum, Apocynum medium var. medium, Apocynum medium var. vestitum) - Flowers pink and 4.5-6 mm long. Calyx at least half as long as the corolla. Plants 20-60 cm high. Leaves subsessile to petiolate and often ascending.
Indian Hemp, Clasping-leaved Dogbane: Apocynum sibiricum - Flowers white to greenish-white and slightly larger than in A. cannabinum. Plants 30-100 cm high. Leaves subsessile to sessile, often with clasping, cordate bases.
Milkweeds: The Genus Asclepias
Periwinkle, Greater Periwinkle, Bigleaf Periwinkle, Vinca: Vinca major - Flowers large (3-5 cm wide) and blue. Plants are viny and serve as a domestic groundcover.
Common Periwinkle, Lesser Periwinkle: Vinca minor -