As a teenager, Geyer worked as an apprentice-gardener in
Zabeltitz, and in 1830 became an assistant at the
botanical gardens in Dresden. From 1835 to 1844 he performed botanical studies on several expeditions within the United States. In 1838-40 he worked as a botanist in the Upper Midwest for
geographer Joseph Nicollet (1786-1843), and in 1841-42 collected plants in
Illinois,
Missouri and the
Iowa Territory for botanist
George Engelmann (1809-1884). Geyer distributed duplicate specimens in an
exsiccata-like series with partly handwritten labels and without title. Afterwards he joined explorer
William Drummond Stewart (1795–1871) on an expedition through the present-day states of
Nebraska and
Wyoming. Eventually, Geyer parted company with Stewart, and performed extensive botanical research in what would later be known as the
Oregon Territory. The plant specimens Geyer collected in 1843/44 were supposed to be sent to
George Engelmann in exchange for Engelmann paying most of the expense of outfitting Geyer for the journey. However, Geyer left the U.S. west coast by boat, and sailed to England, delivering the plant specimens to
William J. Hooker at
Kew instead. Geyer has a number of plant species named after him, including
Allium geyeri (Geyer's onion) and
Euphorbia geyeri (Geyer's
spurge). His botanical collection of nearly 10,000 specimens was acquired by the
Royal Botanical Gardens at Kew. (in what is now Washington State, U.S.) drawn by Charles A. Geyer in 1843. == References ==