German-born botanist and collector for Asa Gray to whom he supplied specimens from New Mexico, Venezuela, Trinidad and Panama between 1846 and 1850. Elected a correspondong member of the Academy in 1868. He was a friend and assistant of W. M. Canby, and while living in Wilmington prepared his Mechanics of the Universe, privately published in 1876, which contained advanced ideas now accepted in speculative physics. The manuscript for the latter is preserved with Canby's papers at the Wilmington Institute, as reported by Frank Morton Jones, 1959. The papers consist of two letters to the Academy and a list of Venezuelan plants, a broken series from number 9 to 2623, followed by a section entitled “Fendler's Chagras Collection.”