Complex sentence: No food analysis has been done, but it is assumed the species diets on green, herbaceous plants such as ferns, grasses, forbs, shrubs, and, unique among cottontails, conifer needles in the summer and woody plants in the winter.
Split into simpler sentences: No food analysis has been done, but it is assumed the species diets on green, herbaceous plants such as ferns, grasses, forbs, shrubs. Uniquely amongst the cottontails, it eats conifer needles in the summer and woody plants in the winter.