Dipteryx odorata (syn Coumarouna odorata) of the family Fabaceae (aka Leguminosae), the legume family (aka pea family). May also include Dipterix micrantha.
Also, there is another species, Dipteryx micrantha, that is more commonly called shihuahuaco and probably SHOULD be distinguished from cumaru, but so many dealers blend the two, and list Dipteryx odorata as shihuahuaco, that it is just not realistic to seperate it out, so it's here too.
SO ... while I say at the top of this page that cumaru is Dipteryx odorata, it is possible (but less likely) that if you buy "cumaru", you will get D. micrantha or D. micrantha instead of D. odorata, but true shihuahuaco (D. micrantha) seems to be a pretty obscure wood, at least in the USA --- it is generally found in Peru where it is used for flooring, outdoor carpentry and other places where its hardness and durability are useful.
Cumaru is a large South American rainforest tree that produces a very grainy but dense and heavy wood; it is sometimes sold as "Brazilian chestnut". The tree produces a berry called the tonka berry and the wood is also sold under the common name tonka, among many others. Lumber color tends to run a wide range over red/brown.
both sides of a sample plank of cumaru / Dipteryx spp. --- HUGE enlargements are present. This sample was loaned to me by David Clark whom I thank for this and other contributions to the site.
end grain and end grain closeup of the piece directly above
flooring sample and end grain, listed as cumaru --- actually, this was listed as "Brazilian teak" which is just a made-up marketing name used by flooring companies, and has nothing to do with the wood and is not used outside of flooring companies, but the alternate name cumaru was also given. When I took this out of the box, I thought it was ipe, and I still point out that even down to the details in the end grain closeup it looks very much like ipe but I do believe it is probably cumaru.
A NOTE ABOUT COLOR --- I don't know whether this piece has turned more red during the 8 or so years it's been sitting in my sample boxes or if I just did a bad job originally of correcting the color of the pics, BUT ... when I did the end grain update below I noticed that this piece is noticibly more red than is shown here and the color in the end grain update is accurate.
plank --- grain shows better in the enlargements; color is quite accurate. Just for grins, I've also posted the vendor's pic of the same plank as it appeared on eBay. This is an HONEST vendor, by the way, just one who cannot afford the time to do color correction on all of the hundreds of pics he has posted at any one time.
both sides of a small piece --- the first pic is a freshly sanded side and the next pic is of a side showing a slight age patina