That's a pilea, common name is probably variegated artillery plant or something close to that. Look it up under Pilea microphylla 'Variegata'. I found another one this spring and have it in a similar container. I'll try to take a pic once it fills out nicely. If you like it, I can send it to you when it starts to cool off. I don't have room to over-winter, though I've over-wintered the green species plant. I wouldn't let it loose in my garden though, if I was considering that option. ;-) Al

PT's habit is to shed older leaves, but root congestion increases the number of leaves shed and decreases the number of leaves the plant is able to retain. (The condition of) tight roots tends to concentrate most of the growth at or near apices (growing tips of stem or branches). Potting up will partially relieve some of the stress of root congestion, but ideally, you would get some help repotting and do a repot and move the plant to a larger pot. You could roll the pot on it's side over a plastic tarp in the garage & go at it there, then repot it into a very fast (draining) soil. If it's suffering from root congestion, there really is no remedy other than 'uncongesting' the roots. Are you sure the split in the bark isn't just a fissure that comes naturally with aging? How did you add magnesium? Epsom salts? Generally, adding single nutrients or products aimed at supplying single nutrients is much more likely to end up being a limitation than a 'boost'. There is no substitute for the combination of a soil you can water correctly and a sound nutritional supplementation program Al

As one of my favorite plants, I usually have a Ponytail Palm in my container collection... though, I'm sad to say that mine got hit by a frost this past autumn and turned to mush. It couldn't be salvaged. Honestly, I'm not sure if you can save it... it doesn't look good to my eye, but... Perhaps someone who knows these plants better than I will come along. I wish you the best with it. They're really nice plants.

Thank you for your comments. It would be nice to save the tree but cutting out tile and its concrete base is not a doable option. The patio is limited in size as it is. Another negative factor is that the tree is leaning to a point that the back end of the elephant foot base is pulling away from the ground. I'm concerned that a high wind, such as those quite prevalent in Florida will cause the tree to come down and destroy the patio fence. ..... I'm wondering how much damage might be caused by pulling it straight up with some sort of a cherry picker. Lifting it over the five foot fence and hauling away to be transplanted elsewhere. ..... Thank you again for your comments. Any additional thoughts would be appreciated.