By 1846 he was established in Albany, where he made at least a partial living as a professional collector of natural history items. He accompanied Drummond to the Stirling Range, Western Australia (1846-1847) and also accompanied Mueller on a number of long journeys. His main collection is in MEL, with substantial numbers also in BM and K. Some are also in B, CANB, KIEL, MANCH, M, PERTH and W.
Extracted from: A.E.Orchard (1999) A History of Systematic Botany in Australia, in Flora of Australia Vol.1, 2nd ed., ABRS. [consult for source references]
"Only two years ago (wrote Mueller to Gard. Chron., 3rd April, I880, p. 433) I made long journeys with him over rough country for several days on horseback to collect plants and seeds. More than 30 years ago he conducted Drummond through the Stirling Ranges in the journey that proved so memorable in the discovery of many splendid plants. He was nearly always in the bush, and engaged in collecting seeds, botanical and entomological specimens. Encouraged by myself, he undertook several extensive journeys over then untrodden ground, eastward as far as the Great Bight, and thus found many new plants and enabled us to extend the known limits of the range of many rare species, as recorded in the Flora Australiensis."
He is commemorated by the following species:-
Eriostemon maxwelli , F.v.M.;
Genosiris maxwelli, F.v.M. = Patersonia maxwelli, F.v.M;
Pimelea maxwelli, F.v.M.;
Poa maxwelli, Benth.
Source: Maiden, J.H. (1909) Records of Western Australian Botanists. Journal of the West Australian Natural History Society. 2(6):5-33