Sentence:  Three of these only were protected from us by stern commandment : the roses , whose petals might not be collected until they had fallen , to be made into perfume or rose tea to drink ; the peonies , whose tight sticky buds would be blighted by the laying on of a finger , although they were not apparently harmed by the ants that <WSD>crawled</WSD> over them ; and the poppies . 
Meaning of the word marked with <WSD> tags:  move slowly; in the case of people or animals with the body near the ground