The first one looks like giant clover (I'm sure its not). I think the second one is mint. I don't feed mint, but I don't know if its edible for tortoises or not. I hate being so ignorant about plants. I need a plant mentor to study under. When I win the lottery, I'm going to go work at a nursery for a year or two. You know, in between all the tropical scuba diving trips, welding lessons, falconry and tortoise pen building.
I was thinking they looked like that two but I am with you Tom I don't know anything about plants, though I am trying to learn. I got these from small strip of land between my grandparents back yard and their neighbors.
First one is definetly clover it grows in my pen but my guys won't touch it. the second one looks like mint but I could not say 100% I am pretty sure it is edible but I think it leaves it up to individual torts.
Look at the difference in leaves between oxalis and clover. Clover do not have "heart shaped" leaves. Oxalis however does. Clover leaves look more like "water droplets"