Czech professional plant collector and distributor from Prague, who initially trained as an engineer. He lived mainly in Dresden and Leipzig. (1825-1829), then for a short while in Paris before moving finally to Prague (1830). His own collections were made during journeys undertaken mainly in the period 1811-1825. He published 23 exsiccatae series with his most important collections from Austria and Italy (1811-1812), from Egypt, Crete and Israel (1817-1818) and from South Africa, Mauritius, Madagascar and Australia (1822-1825). Many of the collections distributed under the name of Sieber were collected by others, for example, specimens from Trinidad (Flora trinitatis) were collected by by F. Wrbna (1822), from Martinique (Flora Martinicensis) collected by F. Kohaut (1819-1821), from Senegal by A. Döllinger, F. Kohaut and J. Schmidt, and much of the material from South Africa (Flora Capensis) was collected by C. Zeyher. Sieber funded his travel through the sale of specimens and by organising a fee-paying exhibition, which included ethnographic objects, the contents of which were later sold to the Bavarian Academy of Science.