Help identifying newly-adopted cactus

[cactusnewbie1]

Hi! I would love any help on identifying this cactus that I recently adopted from a coworker. Photos attached; it's in around a 4-inch pot for reference. Also would love to know if it looks healthy or not

Thank you!

[MadridPeter]

Looks like it has a serious case of rot..with all that brown discolouration..hopefully your colleague was unaware otherwise he or she might have been unloading a dud ..see what others say but once rot sets in your only hope is to cut off any offsets/babies the plant has and start again

[tumamoc]

Could be Mammillaria longimamma.

[cactusnewbie1]

Thanks for the responses! Any advice re: rot would be great. Would love to salvage the little guy if possible!

[iann]

I think it is Mammillaria decipiens. Probably not rotting, just discoloured around the base. Possible got attacked by mites. If it is rotting then iy will deteriorate fast. If it has mites then it will deteriorate slowly Might be worth repotting and then you'll know for sure.

[jmoney]

Nice plant! Hopefully it's not rot. Good luck!

[DaveW]

It's not M. decipiens as tubercles are far too fat. M decipiens tubercles taper uniformly along their length to the areole, as does M. camptotricha. I agree it's probably M. longimamma.

It's a tuberous rooted species, so if the roots are OK the plant is OK and will regenerate. The old tubercles often do go brown and whither and when completely dried can often be pulled off with tweezers. It has probably been kept on the dry side in the past and then lower tubercles do degenerate quicker than on more turgid plants.

If a plant seems to be ailing always knock it out of the pot and see if the roots are OK and remove any rot if present. You can leave the plant laying around a week or so dry root without coming to any harm before repotting. One advantage with cacti they can be left dry root out of the soil provided not left in full sum for up to a month or so without coming to any harm, whereas normal plants may be dead in a week if left that way.

[adetheproducer]

Looks like mammillaria melaleuca, mine is very similar to your at least. The old tubercles do turn brown/yellow when withering and looks a little unpleasant but nothing to worry about.

[DaveW]

I don't think it is M. (Dolichothele) melaleuca Ade. The botanical name melaleuca means "black and white" a reference to the black and white spines that species has. If your plant does not initially have blackish central spines it is not melaleuca.:-

http://www.llifle.com/Encyclopedia/CACT ... _melaleuca" onclick="window.open(this.href);return false;

[vlani]

It is M. longimamma or sphaerica. They differ by the size (longimamma is larger) and flower size (sphaerica is larger). Hard to judge by the picture which one you got.

The brown skin is spider mites, that may or may not still be there.

[cactusnewbie1]

Thanks all for the help! I haven't seen any mites (not sure if they are visible), but I'll hold onto the plant for now and hope it recovers!

[CactusMad]

Hi,it is very hard to see spider mites with the naked eye.They will not just go away on their own,it will just get worse.You could give it a good spray with a good bug killer.

[iann]

Hi,it is very hard to see spider mites with the naked eye.They will not just go away on their own,it will just get worse.You could give it a good spray with a good bug killer.

Its quite easy to see spider mites with the naked eye, but these wouldn't be spider mites. Smaller, no webs, virtually invisible individually, and the plant would be decimated if there were ever enough to see en masse. Unlikely that they left on their own, but possible. Or maybe the previous owner sprayed already.

[CactusMad]

Hi Iann,
What mites are hard to see with the naked eye that don't form webs.I had a plant with such mites and could just make one out moving with a magnifying glass,I wrongly assumed they were spider mites.