Through his collecting he became acquainted with Professor Lehmann of the Hamburg Botanical Gardens, who invited Klatt to organise and run his herbarium.
His subsequent revision of the Iridaceae "Revisio Iridearum" led to his being awarded an honorary doctorate from the University of Rostock and an offer of a professorship which he declined.
Klatt contributed sections on Iridaceae to several publications — "Conspectus Florae Africae" by Durand & Schinz, "Flora Brasiliensis" by Martius, "Symbolæ ad Floram Brasiliæ centralis cognoscendam" by Eugenius Warming and "Baron Carl Claus von der Deckens reisen in Ost-Afrika in den jahren 1859 bis 1865"[1] ("Karl Klaus von der Decken's travels in East Africa in 1859–65").
Klatt's greatest interest though, lay with the Compositae, and his publications on this family covered German East Africa, Madagascar, Australia, Brazil, Guatemala, Colombia and Costa Rica.
He corresponded with and visited Kew, exchanged specimens with Asa Gray and managed to build up a considerable personal collection.