An insectivorous plant in which some leaves are modified to form pitfall traps resembling pitchers containing a liquid. Nectar or other attractants brings insects to the lip of the pitcher. This is slippery, causing the insects to fall in, and specialized cells or downward-pointing hairs prevent escape. The insects drown and are dissolved in the liquid. This plant form has evolved several times and occurs in the families Nepenthaceae (90 species of the Old World tropics), Sarraceniaceae (32 species found in the New World), some members of the Bromeliaceae (bromeliads), and in Cephalotus follicularis (the only species in the family Cephalotaceae) found in south-western Australia.