(n.) One skilled in phytology; a writer on plants; a botanist.

anatomist bacteriologist biochemist biologist biometrist biophysicist bryologist cytologist dendrologist ecologist geneticist herbalist mycologist natural scientist naturalist physiologist phytobiologist phytoecologist phytogeographer phytographer phytologist phytonomist phytopaleontologist phytopathologist phytoteratologist pomologist zoologist