Flytrap Dogbane, Spreading Dogbane: Apocynum androsaemifolium - Both Oregon and Washington have lumped the two following varieties into the same taxon (eliminating the varieties). I've left the photos at the variety level for those who wish to view them as such.
Bitter Dogbane, Spreading Dogbane: Apocynum androsaemifolium var. androsaemifolium (Synonyms: Apocynum androsaemifolium ssp. androsaemifolium, Apocynum androsaemifolium var. incanum) -
Dwarf Dogbane, Flytrap Dogbane: Apocynum androsaemifolium var. pumilum (Synonym: Apocynum androsaemifolium ssp. pumilum, Apocynum androsaemifolium var. tomentellum, Apocynum pumilum, Apocynum pumilum var. pumilum, Apocynum pumilum var. rhomboideum) - Flowers pink and 5-7 mm long. Plants 20-50 cm high. Calyx less than half as long as the corolla. Leaves petiolate and spreading or drooping.
Hemp Dogbane, Common Dogbane: Apocynum cannabinum (Synonyms: Apocynum cannabinum var. angustifolium, Apocynum cannabinum var. glaberrimum, Apocynum cannabinum var. greeneanum, Apocynum cannabinum var. hypericifolium, Apocynum cannabinum var. nemorale, Apocynum cannabinum var. pubescens, Apocynum cannabinum var. suksdorfii, Apocynum hypericifolium, Apocynum pubescens, Apocynum sibiricum, Apocynum sibiricum var. cordigerum, Apocynum sibiricum var. farwellii, Apocynum sibiricum var. salignum, Apocynum suksdorfii, Apocynum suksdorfii var. angustifolium) - 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 xfloribundum (Synonyms: Apocynum androsaemifolium x cannabinum, Apocynum jonesii, Apocynum medium, Apocynum medium var. floribundum, Apocynum medium var. lividum, Apocynum medium var. leuconeuron, Apocynum medium var. medium, Apocynum medium var. sarniense, Apocynum medium var. vestitum, Apocynum milleri) - 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.
Clasping-leaved Dogbane, Indian Hemp: Apocynum sibiricum var. salignum (Now grouped with Apocynum cannabinum according to the USDA website.) - 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.
Bigleaf Periwinkle, Greater Periwinkle, Periwinkle, Vinca: Vinca major (Synonym: Vinca major var. variegata) - Flowers large (3-5 cm wide) and blue. Plants are viny and serve as a domestic groundcover.
Common Periwinkle, Lesser Periwinkle: Vinca minor