Maybe a Red Bud?? I attached a link. Here is a link that might be useful: red bud pods

I can understand anybody's frustration with seed planting of tropicals as sometimes the instructions from the seed source seem the same for every package ... And maybe that's true ... basically the same thing applies to all of them, moist soil, 75 degrees or above, to about 85 degrees. But some of these seeds can be tricky as I have pointed out in my first response to this post. The nice thing about the seeds I show above is that I have about 12 Jacaranda seeds and so can experiment a bit, saving some seeds for when I feel comfortable that I have it tacked. The packet of Tabebuia seeds has 16. I can work with that. My first packet of Tabebuia Chrysostricha seeds was planted all at once and nothing ever germinated. Will I get something later? I don't know. But I got some more seeds to try again under more controlled and experimental ( indoor ) setups. Sometimes that is what you gotta do ... experiment. Look up on the web and find as much info as you can and then try to setup conditions to do the trick. If you had a saltwater aquarium, you'd worry about temperature, Ph and Salinity, Ammonia concentrations, etc. etc. Well, some people germinating seeds get down to doing similar monitoring and adjusting. I don't think we as dumb dodo gardeners need to get so specific, but you may have to try and try again with a different tack until you succeed. Try to think about how plants grow in their native habitat, starting under high canopies, shaded from the sun, perhaps drenched in water, sandy soils with lots of acids from decay products. Without sun they only get as tall as perhaps two to three feet, but if they are lucky and an old growth tree topples over and they aren't crushed, the sun will break through the canopy and away they go ... growing to fill the hole as new giant. So seedlings often need to be shaded at first and given sun after they reach a certain maturity. They don't print that stuff on seed packets. You have put yourself there in your imagination after reading up a bit on the plant. Then recreate the temporality of that situation so that the plant starts out shaded and then gets that lucky break when you physically move it and put it out in the sun. Is a Jacaranda a savanah type tree? No. Is it a dry climate tree? Perhaps. Dig into it. This is the fascinating part of growing tropicals. Don't let me spoil it for you by telling you the details. Discover them for yourself. Good Luck and use some imagination to help you achieve your goal.

Some cactus seed, Opuntia for example, are cream coloured and round. Like a spiral going just one turn. They look almost like tomato seeds. Many other cacti seeds are somewhat triangular: Thicker in one end and thinner in the other. Those are black (all I have seen). Joshua tree seeds I dont know. The descriptions I read says only that they are flat.

I just moved to Herndon from NY a year ago, and it never ceases to amaze me the type of tropical vegetation my neighbors have going in their yards! I'm curious though, do you find your tropical garden more active in spring or summer? Also, I noticed one of the palms growing awfully close to your house, are their roots not-invasive enough to hurt your foundation? I keep finding yellow poplar trees and oaks growing next to my house and it worries me that it'll affect the foundation.