[An interesting species for studies on the determination of the twining type in stems: Periploca graeca L. (asclepiadaceae)].

Periploca graeca plants develop simultaneously under both natural and controlled conditions, three types of shoots: short upright shoots, long twining shoots, and long creeping shoots. Short shoots can be compared with long shoots and long twining shoots with long non-twining shoots. The main stem passes successively through an upright stage and a twining stage.