Martynia (Unicorn Plant) was distributed to gardeners across the country by the Connecticut based Murvon Seed Company from the 1930's to the 1960's. They sold a fine domesticated kind that had seed pods only about 3" long, the catalog showed it's use as a dried novelty and called it a "bird plant" because the dried stem of the pod pointed down like a beak and the claws pointed up like tail feathers. TheMartynia plant grew large even in New York and produced attractive tubular spotted lavender and pink flowers. The large leaves were covered with sticky hairs and, as I recall, the plant spread over a couple of square feet. It seemed very much adapted to our cooler garden which is quite different from the varieties that can be obtained today which do best at high temperatures and full sunlight.
Native Seed Search (Tuscon, Arizona) is the source for seed of the Unicorn Plant today, perhaps the only source. They provide seeds of a number of varieties (all white seeded) that have been domesticated by the Indians of the southwest U.S. The Unicorn plant is native to the desert southwest and American Indians use the plant for a number of purposes. The dried black pods can be split into strips which provide the decorative black in woven baskets. The seeds can be eaten as a protein rich food and the young pods can be eaten raw, boiled or pickled.
I've munched on the dry seed on occasion but can't recommend them for snacking. The young pods are interesting as a vegetable. Both raw and lightly steamed they have a nice consistency. Some people have described the young, tender pods as tasting a lot like okra. I can see the similarity. Without further preparation, the bitterness may not appeal to many people though. I haven't tried pickling the pods yet nor breading and frying them.
When the pods mature and dry the fruit outer covering falls off revealing one tough capsule which readily splits open giving rise to two slightly coiling prongs. The prongs are adapted to snaring the foot of a desert animal, hitching a ride as seeds scatter out the open end. Seed pods lying around in the garden will do the same to unwary humans and the tips of the prongs are sharp enough to break the skin at your ankle. No wonder the ranchers of the southwest worry about the wounds that their livestock can sustain from what they usually call, "Devil's Claw". Introduced into tropical ecosystems this plant has become, in some regions, invasive. It should not be planted unless the spread of seed can be controlled. The Unicorn Plant is not the same plant as the "Devil's Claw" native to Africa and used as a medicinal herb.
Seed of the Unicorn require plenty of warmth and moisture to germinate. The plants resist drought once they are established but prefer the same kind of attention you would give to a tomato plant. We start them early indoors in a peat or compost mix and then set them outside when it becomes warm in late May.