The Kind of plants that Russian and other Tortoise's like to eat are
Antirrhinum - flowers & leaves,Aubretia - flowers & leaves, Bindweed - flowers & leaves,Bramble - Leaves only, Cactus, opuntia (Prickly pear/Indian fig) and Campanula.
They also like to eat any green vegetables that are leafy such as lettuce but it's best to avoid giving your Tortoise Celery since it's rich in Sodium and can cause digestive problems.