cactus of serra da capivara, pi, brazil

alagoas biodiversity caatinga cactus capivara ceara cereus desert desertification drought dryland flower forest gounellei hot jamacaru melocactus melon natural nature nonato northeast outdoor piaui pilosocereus raimundo rays resistance resistant rough sao serra shrubland sky ssp subtropical sun sunshine taxonomy thorn tough tree tropical vegetation water white xeric xique zehntneri