Description

Logwood, Campeche (Haematoxylon campechianum) Blauwhout [NL]
Family: Leguminosae Caesalpinioideae
Dye: Blue-purple-grey
For purple, 15% alum
Blue Grey with 2% Iron(II)sulphate

This dyewood was imported into Europe centuries ago and was an important natural dye for dyeing textiles in Europe.
Logwood is a petit-teint, and was therefore often used in combination with other dyes to achieve a grand-teint.
When you combine a logwood paint bath with a gallnut paint bath you can achieve black.

Facts
Logwood…

… is also called bloodwood
… leaves and bark are also used for medical purposes, for example against respiratory problems or anaemia.
… gives off a lot, so wear gloves 😉 😉
… was a valuable commodity in 1600 to 1800. Often traded by pirates. (wikipedia)

This is one of the products for natural dyes, which are described in the book Eco-verf by Anja Schrik.