Cylindropuntia Species

Per Michelle Cloud-Hughes, Proprietor at Desert Solitaire Botany and Ecological Restoration, from San Diego, California about her above p...Read Morehotos:
"Yesterday I took a short detour on my way home down the road to Grand Canyon Caverns to check out the Cylindropuntia whipplei. This is a spot where the diploids (C. whipplei var. whipplei) and tetraploids (C. whipplei var. enodis -- originally described as Opuntia hualpaensis) occur together and is therefore a likely locality for the original polyploidy event. The two varieties are pretty morphologically similar here, and they become more distinct as you move away from this locality.

For this particular species, by far the best way to tell the varieties apart is the fruit. C. whipplei var. whipplei generally has fertile, tuberculate, bright yellow, thin-walled fruit, while C. whipplei var. enodis generally has sterile, smooth, reddish, thick-walled fruit that often forms short chains. So I'm going with C. whipplei var. whipplei on the ID for this particular plant I found. Maybe next time I'm headed through that area, I'll have more time to poke around and compare."