(Photograph = Crinum lineare, biodiversityexplorer.org)
Introduction
Bulb plants store food and water in the bulb, which is underground. Many bulb plants have fleshy leaves that hold water even if they are not exactly succulent. In northern climates the underground bulb provides protection against freezing temperatures. In other areas the bulb provides protection against drought.
The Details
Crinums are a genus of bulbous plants that extend from Africa to Asia and the Americas. Depending upon how they are classified, Crinums are even found in the deserts of Australia. Many Crinums grow in seasonally wet areas.
Crinums grow in savannas, grasslands, and semi-deserts of Africa in areas that are wet some years. These wadis and shallow ponds remain dry except in rainy years. Sometimes several years pass before they fill with water; in the meanwhile they are brick dry. During that time the Crinum bulbs sit quiescent in the ground. When it finally rains the bulbs send up fleshy leaves and flashy lily-like flowers. They go dormant again when drought returns.
The sometimes giant bulbs stay protected in the dry soil, often a foot or more below the soil surface. Crinum bulbs can survive extreme drought in desert-like conditions while they live underground. Their ability to survive on limited water rivals that of many cacti. However, their ability to thrive in flooded conditions is distinctly uncactus like.
Because the leaves are fleshy and because the huge bulbs can survive extreme drought, it is tempting to speculate that Crinums as succulents. Of course, they are not typical succulents, but they store water for years in their tissues–an important characteristic of succulents.
Additional Reading: Taxonomy of Crinums