Rabbit-tobacco
Rabbitbrush
Rabbitfoot Clover
Rabbitsfoot Grass
Racemed Milkwort
Radish
Radishroot Woodsorrel
Ragged Marsh-elder
Ragged Nettlespurge
Ragleaf Bahia
Ragweed
Ragwort
Railwaycreeper
Rainbow Cactus
Rainlily
Rampion Bellflower
Rare Loco Milkvetch
Rat-tail Nipple Cactus
Ratany
Rattlebox
Rattlesnake Fern
Rattlesnake Flower
Rattlesnakeroot
Rattleweed
Ravenfoot Sedge
Rayless Goldenrod
Red Amaranth
Red Barberry
Red Bluet
Red Brome
Red Buckeye
Red Chokeberry
Red Clover
Red Columbine
Red Cyphomeris
Red Dome Blanketflower
Red Fescue
Red Grama
Red Hoarypea
Red Lovegrass
Red Maple
Red Milkweed
Red Mulberry
Red Pricklypoppy