Delphinidin

- Contractile Roots
Some herbaceous dicots and monocots have contractile roots that pull the plant deeper into the soil. Many lily bulbs are pulled a little deeper into the soil each year as new sets of contractile roots are developed. The bulbs continue to be pulled down until an area of relatively stable temperatures is reached.

Plants such as dandelions always seem to have the leaves coming out of the ground as the top of the stem is pulled down a small amount each year when the root contracts. The contractile part of the root may lose as much as two-thirds of its length within a few weeks as stored food is used and the cortex collapses.

- Buttress Roots
Some tropical trees growing in shallow soils produce huge, buttresslike roots toward the base of the trunk, giving them great stability. Except for their angular appearance, these roots look like a part of the trunk.