(n.) One skilled in the knowledge of plants; a collector of, or dealer in, herbs, especially medicinal herbs.

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