I think it's Mirabilis jalapa/Four O'clock.

Yeah, it's that one that folks don't know the name of. :) Seriously, no, there isn't a plant with the official name of Mystery Plant. You see monikers like that tacked onto ordinary plants in those cheap Sunday supplements and low-end garden catalogs to entice naive gardeners. And sometimes people just attach a "name" like that to a plant cuz they don't know the real name, and then pass it along. Although many folks have an aversion to scientific names, this is why they exist. Common names are all over the map, and are often unhelpful in telling you what plant you've got. Get a little more info from the guy, anything he can remember about the plant such as plant habit (e.g. bushy and clumping? running like a groundcover? etc), height, leaf shape (e.g. strap-like? heart-shaped? etc) and arrangement (e.g. rosette? growing off the stems? etc) and flower shape (e.g. daisy-like, petunia-like, etc), bloom arrangement (e.g. in a flat-topped cluster? single bloom? in a spike? etc) and flower color. With that info we could take a good whack at getting an ID. Marty

Hi! Those small plants are baby maidenhairs. I need help identifying the white stem on the left side. Just edited the post thanks! -kc

Thank you so much for your help. After going to the link above and seeing the photos of the Skunk Currant, I'm thinking that very well may be what I have here. I would have preferred a prettier name however. :) Again, thank you. Off to read more about it. According to the profile of the Skunk Currant, it doesn't grow as far south as Texas. How odd.