Agreed with Rina above, looks like physical damage. Any whitish pock-marks or scratches in a line/pattern are usually dried sap from self-inflicted damage (or damage from other nearby cacti). The crusted white parts on the edges are where the thorns have broken off and healed. Here is a photo I just took of my Euphorbia Trigona, where it sustained a small amount of damage while being repotted a while back (I had rolled it up together with newspaper): Also agree with Stush - mine is growing quite quickly as of late and it's hard to control! It's around 3-4ft as well.

I do like the own root idea but to get so many plants so cheaply grafting is the only way to go. Own roots are better in the long run. Own root roses are far better than the grafted ones. No suckers to worry about but with all good, there is bad. Some of the wild root stock is hardier and can take more disease and bug infestations. So like life, it is a trade off.

Impressive to see the amount of crested heads on a single graft. I would think the graft would have snapped or broken by the weight and the amounts of the crested heads. Not sure why white ghost does green reverting but yours isn't the only one The last pic E. trigona ' milk tree' looks just a little angry, good job. Reminder be careful when bringing them in.

Westes - I suspect the bark just helped retain too much water because I was getting root rot. And I live in an area that's very dry in the summer. Here's the problem with Al's argument: it's all based on the idea that perched water is this huge bogeyman that's killing everyone's plants. It is not. Yes it's a bit of a problem for beginners, but with a little experience, anyone can learn how not to overwater your plants. Al would have you believe that in order to solve a relatively minor problem, you have to go through this enormous ritual of collecting all these different ingredients, sifting them, rinsing them, and mixing them in a certain ratio. Beginners are the last people we should be pushing this on. Instead we should teach them how not to overpot, and how to tell when your soil has dried out. Pretty simple. Other issues: - One of Al's big selling points is the air spaces in gritty mix. But a good organic mix (I use 50/50 potting soil and perlite) will have plenty of air circulation. And when I unpotted some of my gritty mix pots, the mix was pretty compact (and I screen out the small bits). - It's difficult to know when it's the right time to water gritty mix, because it's so heavy. Organic mixes are so light, that you can tell by the weight of the pot if the soil is still wet. - When gritty mix pots fall over, the mix all comes out. With robust plants in an organic mix, the root ball will hold together. Minor inconvenience, but it happens occasionally. - For my plants that survived the move to gritty mix, it took them WAY longer to adapt and start growing then it did for plants I repotted in soil mix. And during that time, many did poorly and I could never tell if it was because they needed more water or less. From an overall cost/benefit perspective, I haven't seen any significant benefits, AND it was a huge hassle to assemble all the ingredients, AND I lost a lot of great plants. Btw I was not coming at this as a beginner. At the time I started experimenting with gritty mix I had 15 years experience growing cacti and succulents in pots very successfully, with a collection of about 120 plants.