Yaqui Indians in the interior, he crossed the Gulf of California to the peninsula of Lower California and went thence by sea to San Francisco. Among the plants collected in northern Sonora and along the shores of the Yaqui River, many proved to be species hitherto unknown. One of them, a columnar cactus, had fruit densely covered with spines, which was used by the Indians for brushing their hair. This was named Cereus pecten-aboriginum by Engelmann, and afterwards described by Sereno Watson in Volume 21 of the Proceedings of the American Academy.
Dr. Palmer next went to Utah. He carried with him a letter of introduction to Brigham Young, who assisted him most willingly in his work by giving him letters to the authorities in the southern part of the territory. His work was chiefly in the vicinity of St. George, in the southwest corner of the territory. This region, considerably lower than the great Utah basin, is remarkable for its semitropical products, such as pomegranates, cotton, etc., on which account it is sometimes called Dixie Land. From St. George he made a long and painful journey across what is now the southern corner of Nevada to Hardyville and Camp Mohave, on the Colorado River, and thence across southern California to San Francisco.
On his return to Washington, in November, 1870, he received a letter from Dr. Torrey, congratulating him on the successful accomplishment of his mission. "I had anticipated much pleasure," Dr. Torrey wrote, "in spending several days with you at the agricultural department, and in hearing from you an account of your doings and adventures.
"You have, in the last few years, done great service to North American botany, and I trust that we shall receive yet greater benefit from your explorations. There are many choice plants to be found in our little-explored states and territories.
"I should be delighted to look over your late discoveries, and I hope you will be able to spare me duplicates. It is of great importance that the herbarium of Columbia College should be as complete as possible in North American plants."
The commissioner of agriculture, Horace Capron, in his report for 1870, calls special attention to the collections of Dr. Palmer and states that the botanical material accumulated by him "is now in process of elaboration by the distinguished American botanists, Drs. Gray, Torrey and Engelmann, and includes a considerable number of plants new to science which will be greatly prized by scientific botanists, and eagerly sought by botanical institutions at home and abroad."
"The design of establishing at the seat of government a collection of plants worthy of the name of a national herbarium is thus in process of rapid accomplishment, at a comparatively small cost; and it is confi-
