Malpighia emarginata, Acerola
Acerola, or Barbados Cherry, is a small tree or shrub.
The seed is hard to get as few vendors carry it. If the seed is fresh (2-3 months old) some seeds will germinate in 2 weeks and others will take up to 6 months. The germination rate is low and gets worse the older the seed gets.
If you are lucky enough to get fresh seed, plant it in potting soil and keep it warm.
I bought my seed from an vendor on Ebay. Sadly, he is no longer there.