A living fossil in the desert
The plant Welwitschia mirabilis is a true botanical oddity and a relic from the Jurassic period. It is the only species in its genus, the only genus in the family Welwitschiaceae, and the only species in its order, Welwitschiales. It is a unique living fossil, with its closest relatives being conifers and the other gnetophytes, Gnetum and Ephedra. Found exclusively in the Namib Desert of Angola and Namibia, it consists of just a stem base, roots, and two leaves.
The entire plant shows extreme adaptation. Its woody, obconical stem grows to be about 50 cm high on average, though some specimens reach 1.8 meters. From this sturdy base, the plant grows its two and only two leaves. These are the original seedling leaves, or cotyledons, which never fall off and grow continuously from a basal meristem for the plant's entire life. In the harsh desert conditions, the leaves grow at an average rate of 8-15 cm per year, eventually fraying and splitting resembling a heap of greenish ribbons. One of the largest specimens recorded has a width of 8.7 meters. Radiocarbon dating has confirmed some individuals are over 1,500 years old, with scientists estimating the oldest may exceed 2,000 years.