(Photo 1)  Haworthia emelyae v. comptoniana.
The tuberose roots of this succulent geophyte are  Contractile  and pull the plant deeper into the soil to protect the perennating bud from sun and heat during the dry season.

Geophytes are a kind of plant having the capability to survive arid  environmental conditions by dying back to underground storage organs. Storage organs are reserves of food (e.g. carbohydrates, proteins), nutrients (e.g. mineral salt), and water, and may be classified as bulbs, corms, rhizomes, stem tubers, root tubers, and enlarged hypocotyls (caudex).
This phase in geophyte development is often referred to as a dormancy period or resting stage; however, such terms are misleading. The storage organ is never physiologically dormant even when aerial growth is halted. It continues to change and constantly senses its environment so the term "dormancy" will more properly refers to the period of the geophyte life cycle when there is no above-ground tissue.
The above ground portions of the plant (usually annual deciduous shoots or leaves) typically die off during the dry parts of the year or in the winter season leaving only the storage organs in the soil, but the plant is able to "re"-sprout when the environmental conditions are appropriate using the food reserves in the underground portion and as a result, geophytes in their natural habitats are capable of perennial life cycles.
Most geophytic plant species may be propagated by division or proliferation of the underground  structure such as a bulbs, rhizomes, tubers,.