What is "androstachys"

Androstachys johnsonii, the Lebombo ironwood, is a medium-sized Afrotropical tree species, and the sole member of the genus Androstachys in the Picrodendraceae. It is slow-growing, evergreen to deciduous, and dioecious, with flowers that are wind-pollinated. It is native to southeastern Africa and Madagascar, where it generally occurs gregariously on rocky hillsides, particularly in hot and dry situations. It produces a hard, durable wood which is of economic interest. Its specific name commemorates W. H. Johnson, a 19th century Director of Agriculture in Mozambique. Four related species which are native to Madagascar, are usually placed in genus Stachyandra.