Answer:
I start with T end with T and within me is T.
I am flora not fauna. I am foliage not trees. I am shrubbery not grass.
I have no voice but I can teach you all there is to know. I have spines and hinges but I am not a door. Once I've told you all, I cannot tell you more. What am I?
Crooked as a rainbow and slick as a plate, ten thousand horses can't pull me straight. What am I?
I'm where yesterday follows today and tomorrow is in the middle. What am I?
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.