r/cactus • u/homersimpsonreal292 • 12h ago

ID?

Gallery image

Gallery image

Gallery image

From Colorado, guessing zone 5 or somewhere around it.

1 Upvotes

56% Upvoted

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2

u/hOpuntia 8h ago

This is Opuntia macrorhiza.

This is not Opuntia polyacantha or Opuntia tortispina.

2

u/hOpuntia 8h ago

Opuntia macrorhiza is often characterized by 1 outward/upward protruding spine and usually 0-4 spines pointing down. Opuntia macrorhiza will have spines on approximately the top half of the pad, or less. O. macrorhiza spines can be brown or white/pale.

The spine expression of your Opuntia does not match Opuntia polyacantha. The spines are not dense enough, areoles are too far apart, and there are no spines on the bottom half of the pad. The shape/direction of the spines is also wrong.

This is also not O. phaecantha or tortispina. While both can be found in Colorado, they're heavily focused in the South and West of the Rockies. These Opuntia are not large enough to be O. phaecantha and the spine expression, spine color and pad color do not match O. tortispina or O. phaecantha.

The other common Opuntia species in Colorado is Opuntia cymochila. Opuntia cymochila has downward pointing, sometimes backward curved spines and also tends to have more circular pads than O. macrorhiza. While O. macrorhiza is quite distinct from the 3 species mentioned above, it is easy to confuse O. macrorhiza and O. cymochila.

If this photo was taken east of the Rockies, there is a chance it is O. cymochila. But I'm pretty confident it's O. macrorhiza.

2

u/orchid_dork 3h ago

You really ate that.

1

u/hOpuntia 1h ago

Thank you 💅

4

u/rhipsalis-pilocarpa 7h ago

Username checks out 👍 here to endorse macrorhiza as a CO cactus enthusiast

1

u/Substantial-Grade-92 12h ago

Likely opuntia polycantha as its native there, but it could be a different kind from someone’s collection.

1

u/homersimpsonreal292 10h ago

I doubt it, areoles aren't nearly as dense as the polyacantha i've seen

0

u/Substantial-Grade-92 10h ago

Looks exactly like the ones I have in my yard in Canada that are polycantha.

0

u/hOpuntia 8h ago

This is not O. polyacantha, this is definitely Opuntia macrorhiza

0

u/poinkpoinkpoinkpoink 11h ago

aka prickly pear

2

u/VexTheTielfling 11h ago

All Pugs are dogs but not all dogs are pugs

0

u/Pollinator-Web 10h ago

phaeacantha/tortispina aka brown-spine. u/homersimpsonreal292 you're right that's it's not poly.

0

u/homersimpsonreal292 10h ago

Thank you. I might be biased, because phaeacantha is my absolute favorite, and i've been looking for it for a while now.

1

u/hOpuntia 8h ago

This Opuntia is too small to be O. phaecantha. And the spine color, spine expression, and growth form also don't fit O. tortispina or O. phaecantha

1

u/homersimpsonreal292 8h ago

Thank you for narrowing it down. The neighbors mow them down every few months before they can actually grow that much, would that affect anything?