Although the succulents as a whole may be considered to be the most tough and resilient group of plants in the world, being able to withstand extreme temperatures and drought, one of the most tenacious is Kalanchoe delagoensis. This small and unassuming plant is commonly known as “Mother of Millions,” a name which it has rightfully earned. Kalanchoe delagoensis reproduces by pollination and the formation of seeds, as do all flowering plants, but it has an additional method of reproduction that few other plants have. At the tips of its leaves, K. delagoensis forms small plantlets that are able to be dislodged from the mother plant and immediately take root to form a genetically identical plant. In fact, almost any part of the mother plant can be broken off and form a new plant. With multiple forms of reproduction, K. delagoensis can create an impressive amount of offspring in one season. Kalanchoe delagoensis is also extremely resistant to drought yet can survive in moist climates as well, and can grow just about anywhere. These abilities allow K. delagoensis to outcompete other species for land and quickly colonize new areas.
Unfortunately, the abilities that are advantageous for K. delagoensis are often problematic for other species. Kalanchoe delagoensis has been introduced from its native Madagascar into much of the world and has become a serious problem in Australia, southern Africa, the Pacific islands, Central America, and the southern United States. Kalanchoe delagoensis can move into areas of low fertility and quickly outcompete native plant species, putting many at risk of extinction. In addition to the effect on other plant species, K. delagoensis contains toxins, known as bufadienolides, that cause heart failure in animals. Kalanchoe delagoensis uses these toxins as a passive defense mechanism to prevent herbivory, but when introduced into new areas the animals of that area are unaware of the potential danger and many animal species are also threatened by this prolific invader.
 Armstrong, T. (1983). Weeds of Australia. Crassulaceae—the mother of millions. Australian Weeds 2:146-151.
 Price-Rees, S.J., Brown, G.P. & Shine, R. (2012). Interacting impacts of invasive plants and invasive toads on native lizards. American Naturalist 179:413-422.