how do you know something is a cnidarian
Cnidaria Cnidarians form an animal phylum that are more complex than sponges, about as complex as ctenophores (comb jellies), and less complex than bilaterians, which include almost all other animals. However, both cnidarians and ctenophores are more complex than sponges as they have: cells bound by inter-cell connections and carpet-like basement membranes; muscles; nervous systems; and some have sensory organs. Cnidarians are distinguished from all other animals by having cnidocytes that fire like harpoons and are used mainly to capture prey. In some species, cnidocytes can also be used as anchors.[9]
Pennisetum As currently envisioned, Pennisetum is a genus of 80 to 140 species.[7][10][11][13] The various species are native to Africa, Asia, Australia, and Latin America, with some of them widely naturalized in Europe and North America, as well as on various oceanic islands.[2]