Meadow Buttercup, Showy Buttercup: Ranunculus acris (Synonym: Ranunculus acris var. latisectus) -
Dwarf Plantainleaved Buttercup, Dwarf Plantain-leaved Buttercup, Plantainleaf Buttercup: Ranunculus alismifolius var. alismellus (Synonym: Ranunculus alismaefolius var. alismellus) -
Plantain-leaf Buttercup, Plantain-leaved Buttercup: Ranunculus alismifolius var. alismifolius (Synonym: Ranunculus alismaefolius var. alismaefolius) -
Davis' Buttercup: Ranunculus alismifolius var. davisii -
Hartweg's Buttercup: Ranunculus alismifolius var. hartwegii (Synonyms: Ranunculus alismaefolius var. hartwegii, Ranunculus hartwegii) -
Leafy Water Buttercup, White Water Buttercup: Ranunculus aquatilis var. aquatilis (Synonyms: Ranunculus aquatilis var. hispidulus, Ranunculus trichophyllus var. hispidulus) -
Water Buttercup: Ranunculus aquatilis var. diffusus (Synonyms: Ranunculus aquatilis var. capillaceus, Ranunculus aquatilis var. porteri, Ranunculus aquatilis var. subrigidus, Ranunculus longirostris, Ranunculus subrigidus, Ranunculus trichophyllus) -
Corn Buttercup, Field Buttercup, Hungerweed: Ranunculus arvensis (Synonym: Ranunculus arvensis var. tuberculatus) -
Southern Oregon Buttercup: Ranunculus austro-oreganus (Synonym: Ranunculus austrooreganus) -
Shore Buttercup, Alkali Buttercup, Seaside Buttercup: Ranunculus cymbalaria (Synonym: Ranunculus cymbalaria var. saximontanus) -
Snow Buttercup, Eschscholtz's Buttercup, Subalpine Buttercup: Ranunculus eschscholtzii var. eschscholtzii -
Snow Buttercup, Suksdorf's Buttercup, Timberline Buttercup: Ranunculus eschscholtzii var. suksdorfii (Synonym: Ranunculus suksdorfii) -
Yellow Water Buttercup: Ranunculs flabellaris (Synonym: Ranunculus delphiniifolius) -
Creeping Buttercup, Creeping Spearwort, Lesser Spearwort, Greater Creeping Spearwort: Ranunculus flammula var. flammula (Synonym: Ranunculus flammula var. angustifolilus) -
Creeping Buttercup, Creeping Spearwort, Lesser Spearwort, Greater Creeping Spearwort: Ranunculus flammula var. ovalis (Synonyms: Ranunculus filiformis var. ovalis, Ranunculus flammula var. samolifolius, Ranunculus reptans var. ovalis) -
Creeping Buttercup, Creeping Spearwort, Lesser Spearwort, Greater Creeping Spearwort: Ranunculus flammula var. reptans (Synonyms: Ranunculus reptans, Ranunculus reptans var. filiformis) -
Elliptical Buttercup, Sagebrush Buttercup: Ranunculus glaberrimus var. ellipticus (Synonyms: Ranunculus ellipticus, Ranunculus glaberrimus var. buddii) -
Wax Buttercup, Sagebrush Buttercup: Ranunculus glaberrimus var. glaberrimus (Synonym: Ranunculus glaberrimus var. typicus) -
Gorman's Buttercup: Ranunculus gormanii -
Modest Buttercup: Ranunculus grayi (Synonyms: Ranunculus gelidus var. grayi, Ranuculus verecundus) -
Downy Buttercup: Ranunculus hebecarpus -
Lob's Water Buttercup: Ranunculus lobbii -
Macoun's Buttercup: Ranunculus macounii (Synonyms: Ranunculus macounii var. macounii, Ranunculus macounii var. oreganus) -
Spiny-fruit Buttercup, Spiny-fruited Buttecup: Ranunculus muricatus -
Western Buttercup: Ranunculus occidentalis var. occidentalis (Synonyms: Ranunculus occidentalis, Ranunculus occidentalis var. dissectus, Ranunculus occidentalis var. eisenii, Ranunculus occidentalis var. howellii, Ranunculus occidentalis var. rattanii, Ranunculus occidentalis var. ultramontanus) -
Bird's Foot Buttercup, Straightbeak Buttercup: Ranunculus orthorhynchus var. orthorhynchus (Synonyms: Ranunculus orthorhynchus ssp. alaschensis, Ranunculus orthorhynchus var. alaschensis, Ranunculus orthorhynchus var. hallii) -
Large-flowered Swamp Buttercup, Straightbeak Buttercup: Ranunculus orthorhynchus var. platyphyllus (Synonym: Ranunculus orthorhynchus ssp. platyphyllus) -
Small-flower Buttercup, Small-flowered Buttercup: Ranunculus parviflorus -
Pennsylvania Buttercup: Ranunculus pensylvanicus -
Mountain Buttercup, Popular Buttercup: Ranunculus populago -
Creeping Buttercup, Double-flowered Creeping Buttercup: Ranunculus repens (Synonyms: Ranunculus repens var. erectus, Ranunculus repens var. glabratus, Ranunculus repens var. repens, Ranunculus repens var. repens) -
Hairy Buttercup: Ranunculus sardous -
Obscure Buttercup, The Dalles Mountain Buttercup: Ranunculus triternatus (Synonyms: Ranunculus glaberrimus var. reconditus, Ranunculus reconditus) -
Little Buttercup, Woodland Buttercup: Ranunculus uncinatus (Synonyms: Ranunculus bongardii, Ranunculus bongardii var. bongardii, Ranunculus bongardii var. tenellus, Ranunculus occidentalis var. parviflorus, Ranunculus uncinatus var. parviflorus, Ranunculus uncinatus var. uncinatus) -