That is Albert Spear Hitchcock (1865-1935), in 1888, with vasculum slung over his shoulder (just try to find one like that nowadays). His peers wrote of him, "[H]e set a rare example in the intimacy with which he penetrated the private life of the plants he studied. At the same time, his love of the grasses was so spontaneous and so strong that he never wasted an opportunity to extend his knowledge of them" From 1928 until his death in 1935, he was principal botanist in charge of systematic agrostology in the U.S.D.A.
This is Willis Linn Jepson (1867-1946), late Professor of Botany at University of California, Berkeley. He systematically collected and identified every plant in California, and among numerous other achievements, is one of the three original founders (with John Muir and Warren Olney) of the Sierra Club. One of the great pleasures of my youth was taking Tarthang Rinpoche to visit the Jepson Herbarium at U.C. Berkeley, and seeing Jepson's original specimens.
In 1913, writing in his journal, just a few miles over the hill from my usual haunt, Jepson reflected:
"Sitting here on the ground studying flower parts under the lens is a pleasant occupation. When one's eyes tire there are the desert ranges stretching one beyond another, and a soft breeze blowing from the west."
So it was then, so it was today.