An encyclopaedia of plants; etc.

MLA

Loudon, J. C. An Encyclopaedia of Plants; Etc. London: Longman, Rees, Orme, Brown, and Green, 1829.

APA

Loudon, J. C. (1829). An encyclopaedia of plants; etc. London: Longman, Rees, Orme, Brown, and Green.

Chicago

Loudon, J. C. An Encyclopaedia of Plants; Etc.. London: Longman, Rees, Orme, Brown, and Green, 1829.