We went ahead and cut the veins out and washed and stored the leafy part of the the leaves. I tasted the leaf and it wasn't bitter. For all intents and purposes it seems edible. Thank you so much flowerbug for your help.
I'm in my second year gardening vegetables and I'm a bit stumped here. I could use some help.
I planted butterleaf lettuce
and was harvesting every couple days from the bottom of the plant. We live at the beach where it rarely gets over 70°. We had TWO days of 75°, I didn't harvest...