Rabbit Ear Rockcress
Rabbitbrush
Rabbitsfoot Grass
Radish
Radishroot Woodsorrel
Ragged Marsh-elder
Ragged Nettlespurge
Ragged Rockflower
Ragleaf Bahia
Ragweed
Ragweed Sagebrush
Ragwort
Rainbow Cactus
Rainbow Hedgehog Cactus
Rancheria Clover
Ratany
Rattlebox
Rattlesnake Fern
Rattlesnake Plantain
Ravennagrass
Ravine Fescue
Ray Hymenopappus
Rayless Goldenhead
Rayless Shaggy Fleabane
Rayless Tansyaster
Recurved Milkvetch
Red Amaranth
Red Baneberry
Red Barberry
Red Bluet
Red Brome
Red Clover
Red Dome Blanketflower
Red Elderberry
Red Fescue
Red Goosefoot
Red Grama
Red Hoarypea
Red Inkplant
Red Star-thistle
Red Triangles
Red Valerian
Red Willow
Red-gland Spurge