The plants called Adenium arabicum in Oman are substantially different from the plants in Yemen and Saudi Arabia that are properly called A. obesum. The Oman plants are characterized by a broad, squat caudex up to a meter across.The stems that arise from it are thin and often floppy, and may root when they contact the ground. The leaves are very large, second in size only to those of A. boehmianum. The flowers are very small and appear in late spring while still leafless. Finally, the plants have a very short growing season and are extremely slow. These may warrant at least subspecific status; more study is needed.
|Adenium cf. arabicum, Oman form. The plant above is in a 6-inch pot and is 3 years old. A Yemen or Saudi arabicum of this age could be filling a 12-inch pot.|