You're in luck... I just ordered the Brugmansia and Datura book by Ulrike and Hans-Georg Preissel. It just arrived today. According to the book,
"D. inoxia grows upright into a shrub about 1 1/2'-7' in height. The young shoots of the green plants are covered thickly with numerous glandular hairs that become fewer on older sections. The soft leaves are a broad oval shape. The leaf edges are whole, but occasionally undulate and toothed in the lower section. The flowers are about 4" accross and shaped like a funnel. They are 4 1/2-7 1/2 inches long and pure white in color. The greenish veins end in five longer peaks. The interacuminal peak that lie between are noticeably wider and longer than D. wrightii."

"D. wrightii grows into a bush either upright or low lying up to a height of 5 foot. The green shoots of the plant often look as if they are covered with a thin violet layer. All the young leaves are noticeably furry but they become less so as they age. The soft leaves are ovate to broadly ovate. The edge of the leaf is coarsely toothed or gently undulate. The funnel shaped flower corollas are 5-9" long and attain a diameter of 5". The upper section is usually violet to pale violet. Pure white examples are rare."

As far as starting them from seed, they mention 2 inparticular that are contrary to start, neither of these are the ones I've described. It does say that the seeds should germinate at temps around 68*F.

Last year, I soaked some seeds, probably for a couple, 3 or 4 days before I sowed them in my greenhouse this past early spring. A good many of them sprouted and I transplanted them into pots until the weather warmed up. I planted several around the property and was fortunate enough to enjoy their sweet perfume.

Were the seeds aquired from a trade? Maybe they are older seed, maybe harvested too early, not kept in ideal conditions. At any rate, I've got a ton of seeds that I've been harvesting from my D. inoxia that I'd be happy to share with you for SASE. Hope this info helps.

Nancy

Here is a link that might be useful: Brugmansia and Datura book

Thank you, Nancy.

I pick all of my seed pods from existing plants near my property. I try to pick them as often as possible, so as to get a variety of seeds ranging different levels of maturity. I am interested in this seed sharing, but I fear, from your description, that my specimen may, too, be an inoxia. The flowers are typically pure white, though the wood shows some violet, and the seed pods often have violet-tinged areas between the spines. The flowers themselves tend to describe more as D. wrightii, except for colour. I think it would be going out on a limb to say that all of the Datura around here are D. wrightii with pure white flowers. I'll get a few pictures for comparison when I can.

Pardon my asking, but what is "SASE"?

I took some pictures tonight. Unfortunately, my camera does not want to communicate with my computer.What the photographs illustrate is a pure white bloom, erect, maybe five inches in diameter, with five terminal points. The seed pod of the plant in question is globular, perhaps two inches or less in diameter, with spines extending about a centimeter from the surface of the pod, and always drooping down from the branch. I have read that the seed pod of D. inoxia is egg-shaped, whereas the seed pod of the D. wrightii is globular. I have also read conflicting reports which state that D. inoxia produces globular seed capsules, as well. To further the confusion, I've read various sources which state that the flower of D. inoxia has five points, whereas D. wrightii has ten, later contradicting that statement by saying that it's the other way around. An image search on Google slaps me in the face with results showing pictures labeled as D. inoxia blooms, having five of these terminal points, as well as pictures of D. wrightii with five points. The veins on the flowers of the plants which I have observed are hardly visible. I'll take a closer look tomorrow morning. Maybe then my camera will give forth its trove.