We now know - thanks to what I uncovered with the Big Data IDD method - that in addition to the anonymous citations of it and many advertisments for it, that at least 24 named and known people cited Matthew's 1831 book pre-1858. One of these 24 is the economic botanist William Jameson.
From my orignal unearthings in the historic literature we now newly know that Darwin's and Wallace's friends and mentors William and Joseph Hooker, father and son top UK economic botanists, were in regular contact with William Jameson (see Sutton 2014 2017), who we also now newly know cited Matthew's (1831) book in 1853. Jameson wrote about how Matthew explained that trees could grow better in environments that were not their "natural" habitat. This was a religious heresy that confused (at least he conveniently claimed he was confused by it) Selby (Wallace's Sarawak paper editor), who cited Matthew's book on that topic and others back in 1842. It was heresy because Christian doctrine dictated that "God" placed every living thing in the best place (natural habitat) possible for it to be exploited for the benefit of humankind.
Today - as we enter a new paradigm on the history of discovery of evolution by natural selection that views Darwin and Wallace as serial lying, glory thieving, science fraud plagiarizers - there is an interesting book chapter published on the 19th century importance of Matthew's radical economic botany thinking.
Histories of Technology, the Environment, and Modern Britain
by Jon Agar and Jacob Ward. UCL Press, 9 Apr 2018
See Chapter 12 by Mat Paskins: pp. 230-232 on Patrick Matthew. Read the relevant text Here.
"Histories of Technology" demonstrates just how important Matthew's book was in the 19th century for economic botanists such as Darwin's close friends the Hookers of Kew. Indeed Joseph Hooker was Darwin's best friend! Of course Joseph Hooker read Matthew's book before 1858 and told Darwin about it. Of course others such as Wallace's mentor William Hooker, and his editor Selby, told Wallace about it before Wallace wrote a word about natural selection. What planet are radical fact denial Darwiboppers on? demented Planet Darwin Fantasy World, that's where.
Back in the real world, Matthew (1831) used artificial selection as an explanatory analogy of differences to explain his theory of what the IDD method reveals he uniquely coined the 'natural process of selection'. Darwin then uniquely four word shuffled Matthew's term to its only possible grammatically correct equivalent 'process of natural selection'. Darwin had no choice but to so plagiarize Matthew's term because the theory he stole is about a process, that is natural and involves nurture's selection of the best circumstance suited varieties and species. Likewise, Darwin opened Chapter 1 of the Origin of Species by plagiarizing Matthew's analogy of differences between artificial and natural selection. Earlier in 1844, in a private essay, Darwin even used Matthew's highly idiosyncratic forester, botanist,agriculturalist, abroriculturalist, trees raised in nurseries versus those grown in the wild unique analogy of differences (see the facts here).