small cactus on ocean cliffs near San Diego, ID??

[prowat]

Hello, I found a large group of small barrel-like cacti on the top of cliffs 300' above the ocean, near San Diego. They are quite small, about 2-3" diameter and 3-6" tall, in sandy location, but slightly sheltered from the ocean breeze being on the landward side of the cliff. They are NOT "Coast barrel cactus" as I know what these look like. Spines are straight, no fish-hooks. I'll attach four photos. The last photo shows buds "babies?" growing on the top and sides of a parent.
Can anyone identify them?
Thanks, Peter R
===

a group of them

A.Group.jpg (130.67 KiB) Viewed 520 times

B.SanDiegoCoastCactus.jpg (123.09 KiB) Viewed 520 times

C.flowering1.jpg (112.47 KiB) Viewed 520 times

[Saxicola]

I believe that is Mammillaria dioica.

[vlani]

Looks like dioica, probably unusual hookless variant