enough of the subject in the course to make three points for a full year. Asa Gray was professor at Harvard from 1843 to 1875, and during those thirty-two years, with the large undergraduate body of Harvard to draw on, and with the best facilities at that time that were offered in this country, only a single Harvard man of that period ever became a botanist. In fact, it was not the policy of Asa Gray to develop botanists; he was an ambitious man and he thought to hold the higher flora of North America in his own keeping; if any people attempted to do independent work, they were immediately criticized so roundly that only the bravest ever dared show his hand in print again. But there came a revolt. Asa Gray was, to use his own expression, 'a closet botanist.' After his early days in New York he rarely went afield even in the vicinity of his own home. He knew his plants only as they were found in the hortus siccus. He never saw the Mississippi or set foot on a prairie until he was sixty-two, and then took a single hurried trip across the continent with Sir J. D. Hooker. But there were others who studied afield, who knew their plants from their living habits rather than from their fragmentary mummies, and one or two were bold enough to make their own statements in opposition to 'authority' and to stand by them. One of these, a son of New England, but broadened by residence in Illinois, Wisconsin, Colorado and California, raised a standard against the one-man policy that had obtained so long in American botany, and his work was the cause of such mental strain that Gray's nervous tension could not bear it. This revolutionist, stalwart and vigorous, in figure a hybrid between the Farnese Hercules and the Apollo Belvedere, was Edward Lee Greene, and his revolt was the signal for other and younger botanists who soon followed him in the arena. After Gray's death in 1888, the center of study on the North American flora shifted from Cambridge, and new centers sprang up in Washington, at St. Louis, where George Engelmann, one of our German-American botanists, had long been at work, and in California, where Professor Greene then held a university chair. At New York, where botany had been largely dormant since the death of Torrey in 1873, the subject was revived under the leadership of a young man whose modesty forbids my pronouncing a eulogy on him living. To know how well he has developed this center of botanical work one has only to visit the New York Botanical Garden, at once his magnum opus and his monument.
The period just preceding the entrance of some of the older of the present generation of botanists to their college studies was a brilliant one in European botany, but all foreign researches were carefully hidden away from us as youngsters. All the splendid work of Hofmeister, of Nägeli, of Von Mohl and of De Bary was unknown to that group of American college students, and the appearance of Sachs's