extraordinary sensitivity of the roots to high temperatures is currently believed to be caused by a very low and limited optimal temperature of the ion pumps in root cells Modern cultivation efforts in breeding and selecting plants that can withstand higher temperatures without the roots dying back have met with significant success. As a result, there are several cultivars available as commercial house or garden plants which are more tolerant of higher temperatures. Many wild populations grow in serpentine (ultramafic) soils which are toxic to most green plants. Populations found growing on serpentine can withstand soil temperatures above 80 °F based on field studies of various cobra lily populations in Oregon, most of which are found growing on slopes composed of serpentine with cold subsurface water flow. The plants can suffer from root rot in cultivation if grown in stagnant, standing water and tend to thrive in areas where cold subsurface water slowly flows underground around their roots. It is not currently understood why the plants can withstand higher soil temperatures when found growing on serpentine soils. Pitcher mechanisms The cobra lily is unique among the three genera of American pitcher plants. It does not trap rainwater in its pitcher. Instead, it regulates the level of water inside physiologically by releasing or absorbing water into the trap that has been pumped up from the roots. It was once believed that this species of pitcher plant did not produce any digestive enzymes and relied on symbiotic bacteria and protozoa to break down the captured insects into easily absorbed nutrients. However, recent studies have indicated that Darlingtonia secretes at least one proteolytic enzyme that digests captured prey. The cells that absorb nutrients from the inside of the pitcher are the same as those on the roots that absorb soil nutrients. The efficiency of the plant's trapping ability is attested to by its leaves and pitchers, which are, more often than not, full of insects and their remains. The slippery walls and hairs of the pitcher tube prevent trapped prey from escaping. In addition to the lubricating secretions and downward-pointing hairs common to all North American pitcher plants to force their prey into the trap, this species uses its curled operculum (hood) to hide the tiny exit hole from trapped insects and offers multiple translucent false exits. Upon trying many times to escape via the false exits, the insect will tire and fall