In 1753 Carl Linnaeus (Carl von Linné) set out to organize and classify every plant known to man at the time. His work was published in four volumes, Species Plantarum, in sections I – XIII. Thanks to Project Gutenberg, you can read them all for free in their original Latin (Google translate may help):
Species Plantarum, Sections I-III
Species Plantarum, Sections IV-V
Species Plantarum, Sections VI-X
Species Plantarum, Sections XI-XIII
More accessible to read may be Linnaeus’ journal of his 1732 trip to Lapland in Northern Sweden, also available at Project Gutenberg:
Lachesis Lapponica; Or, A Tour in Lapland, Volume 1
Lachesis Lapponica; Or, A Tour in Lapland, Volume 2
Beautiful descriptions of Lapland in 1732 in the spring, still snow on the ground in some places, but early spring flowers starting to come up.
Those interested in plants and classification can find more information at the Plant Information Center website from the UNC Herbarium.