Euphorbia knuthii Family: Euphorbiaceae. A nice multistemmed species that forms tuberous roots that can be raised like a caudex. The stems are square, dark green with white mottling. Easy to grow. Put it in a well draining mix and water when the soil gets dry. Cut back on water in the winter when it is mostly dormant. Protect from frost.
You will receive a plant shown in image 4 or one similar. It is shown growing in a 4" pot. Last image shows a mature plant that has been raised to show the caudex/roots.