Its stem looks like a pitcher and holds liquid. The liquid traps unwary insects which drown and provide food for the plant.
bugs
Insects and other prey of the tropical pitcher plant are lured by its bright and attractive colors and markings, the sugary nectar inside the "pitcher", and the sweet scent it gives off. After the insect enters the pitcher, it becomes trapped in the sticky nectar inside.
no marrow is the liquid inside of your bones
cytoplasm
Pitcher plant pitchers turn black due to the accumulation of dead insects and other organic matter inside the pitcher. This decomposition process causes the pitcher to darken in color.
The pitcher plant,the cobra lily,Venus flytrap, are all very carniverous.The pitcher plant is a very easy to get caught in......if your a insect all it has to do is to fall in there and there would be a liquid at the bottom
A pitcher plant senses changes in air pressure when it's about to rain, and it closes a leaf over it's "pitcher" to act as a lid so that the rain will not diluet the mixture inside.
A 'pitcher' is another name for a jug and they are usually used to hold liquids. There is also a carniverous 'pitcher plant' which grows liquid filled 'pitchers' on the tips of its leaves. Insects and small amphibians are attracted to and fall in these and are then digested by the plant for the nutrients they provide.
This trapping mechanism is for the trumpet pitcher only. The lid is basically an advertisement in the pitcher plant. The bottom side of the pitcher plant is covered with nectar and microscopic downward pointing hair. When any insect comes to collect the nectar the ant gets a downward thrust from the microscopic hair and falls into the liquid. Without the lid the pitcher plant will not be able to catch insects. Referance: David Attenborough [BBC Wildlife]
The cobra lily is a pitcher plant meaning it holds water to attract insects inside its "pitcher". Once an insect is inside, the steep, slippery sides will not allow it to get out easily. Once the prey is captured, the plant releases a digestive enzyme to digest the prey.
Pitcher plants are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid known as a pitfall trap.