Fockea edulis (Apocynaceae) It forms a thick grey tuber, known as a caudex, with small wart-like growths (tubercules) all over the surface. In the wild, the caudex is partially or totally buried and tends to grow faster this way. From the top of the caudex thin vine stems branch out , reaching a length of up to 4 meters. and climb on any type of available support. The caudex can grow up to 60 cm in diameter, and the vines reach 4 meters in height.