After that he continued to devote himself to botanical study, and in 1817 he and Johann Baptist von Spix were sent to Brazil by Maximilian I Joseph, the king of Bavaria.

He devoted his chief attention to the flora of Brazil, and in addition to numerous short papers he published the Nova Genera et Species Plantarum Brasiliensium[4] (1823–1832, 3 vols.)

He also published works and short papers on the aborigines of Brazil, on their civil and social condition, on their past and probable future, on their diseases and medicines, and on the languages of the various tribes, especially the Tupi.

He died at Munich;[3] his gravestone is decorated with two palm fronds and the Latin inscription In palmis semper virens resurgo.

[citation needed] In 2012, botanists Harley & J.F.B.Pastore named a genus of flowering plants from Brazil and Peru, belonging to the family Lamiaceae as Martianthus in his honour.

At the time of his death the collection had been further expanded and comprised 300,000 specimens representing 65,000 species from around the world, and was one of the largest private herbaria assembled.

Plantae Brasilienses exsiccatae, quas denominatas, partim diagnosi aut observationibus instructas botanophilis offert Dr. C. Fr.

[11] The Belgian government acquired the collection in 1870 which formed the basis of the then newly established Jardin botanique de l'Etat.

The first natural history collections were made in the city of Rio de Janeiro at Laranjeiras, Corcovado, Aqueduto, Fonte da Carioca, Tijuca, Botafogo, Jardim Botanico immediately following the wedding.

They left on 9 January 1818 for Sorocaba and Itu on to Minas Gerais, then through Camanducaia to cross the Rio Sapucaí for São Gonçalo and Ouro Prêto.

They departed on 11 May, arriving on 15 May at São Gonçalo do Amarante, where Martius became seriously ill. Spix had at this time contracted the schistosomiasis from which he eventually died.

[16][17] A performance of this work by Orquestra e Coro Vox Brasiliensis & Ricardo Kanji is included in their recording História da Música Brasileira – Período Colonial II.