Botanical cover is a term used to describe the protective outer layer of plants. The two crossword solutions for this term are ARIL and ALOE, both of which are four letters long. An ARIL is a fleshy or papery covering that encloses the seed of some plants, such as the yew tree. Aloe is a succulent plant with thick leaves that contain a gel-like substance, which is often used in cosmetics and medicines.