Welwitschia mirabilis showing top of the stem cone

The stalks of the female cones of Welwitschia mirabilis emerge from the edge of the inverted conic structure of the central stem of the plant. The growth of the stem starts between the two cotyledonary buds of the plant’s beginning. The two normal, life-long leaves grow opposite the elongated cotyledons.

The flat dry top of the obconical stem can be seen in picture. Most of it grows below ground. It can get to about 1 m in diameter at the top, the widest point of the cone. New growth occurs on the edges away from the centre, like the wood of tree trunks where new vascular and cork cambiums are formed on the outside as observed in year rings.

This living edge also continues to grow upwards, even to a height of more than 1 m above ground. The top is thus often undulating. Also the sides of the cone grow unequally, causing the plant to become increasingly distorted as it ages (www.namibweb.com and www.plantzafrica.com).