The pitchers accumulate vast quantities of insects in the course of a season, and must thus abundantly manure the surrounding soil when they die.
Not to speak of insects which feed upon the pitcher itself, some drop their eggs into the putrescent mass, where their larvae find abundant nourishment, while birds often slit open the pitchers with their beaks and devour the maggots in their turn.
Siegburg pitchers (Siegburger Krilge) were widely famed.
In most cases such wheels merely have earthenware pitchers attached to their circumference by means of wisps of esparto, and are turned by a horse harnessed to a long arm fitted to a revolving shaft.
A study of the development of the pitcher, especially in the young pitchers of seedling plants, shows that the inflated portion is a development of the midrib of the leaf, while the wings, which are especially well represented in the terrestrial type of pitcher, represent the upper portion of the leaf-blade which has become separated from the lower portion by the tendril; the lid is regarded as representing two leaflets which have become fused.
- Cephalotus follicularis, showing ordinary leaves and pitchers, the right hand one cut open to show internal structure.
Roots are often flattened, twisted and otherwise distorted by mechanical obstacles; stems by excess of food in rich soils, the attacks of minute parasites, overgrowth by climbing plants, &c. Leaves are especially apt to vary, and although the formation of crests, pitchers, puckers, &c., must be put down to the results of abnormal development, it is often difficult to draw the line between teratological and merely varietal phenomena.
Besides busts and figurines, which belong as a rule to the Greek period, the smaller objects usually found are earthen pitchers and lamps, glass-wares, tesserae and gems. Of buildings which can be called architectural few specimens now exist on Phoenician soil, for the reason that for ages the inhabitants have used the ruins as convenient quarries.
Pitchers are formed either by petioles or by laminae, and they are composed of one or more leaves.
It is generally tubular in form, but in some species two forms are produced on the same plant, lower or terrestrial goblet-shaped pitchers and upper suspended pitchers retaining the more primitive more or less tubular form; in a few species a third form - funnelor cornucopia-shaped pitchers - occurs in the upper part.