JOHN LEONARD RIDDELL.--Born in Leyden, Mass., Feb. 20th, 1807; died in New Orleans, La., Oct. 7, 1863. He graduated from Rensseler Institute, Troy, N. Y. He came to Ohio in 1830 and became professor of Botany and adjunct Professor of Chemistry in the Medical College of Cincinnati. He was an enthusiastic and industrious botanist, and collected extensively in many parts of our State. Scarcely any of his specimens seem now to be in existence though he prepared sets for sale and accumulated a large herbarium. His most important publication was the Synopsis of the Flora of the Western States. He also published a Supplementary Catalogue of Ohio Plants. In 1836 he left Ohio, carrying his botanical specimens to New Orleans where he became professor in a Medical College; he was also in the employ of the government until his death. He furnished many notes and longer articles to scientific journals and was the author of many new species of plants. The following have been named in his honor: Riddellia, synonym of Psilostrophe, a genus of the Compositae family. Solidago Riddellii, a species of Golden Rod. Senecio Riddellii, synonym of S. Douglasii, a species of Compositae. WILLIAM STARLING SULLIVANT.--Born in Franklinton, Ohio, Jan. 18, 1803, died in Columbus, Ohio, April 30, 1873. He was educated at Ohio University and Yale. The death of his father at the time of his graduation prevented him from studying for one of the learned professions and he became a surveyor and practical engineer, which occupation he followed until late in life. During this time he collected and studied the plants of central Ohio, and in 1840 he began to pay particular attention to Mosses; this became the subject of his special study, and he was soon recognized as the most eminent bryologist that this country has ever produced. In 1864 the degree of LL.D. was conferred on Sullivant by Gambier College. He was elected to membership in many scientific societies both in the United States and Europe. At his death his bryological books, collections and preparations of Mosses were given to the Gray Herbarium of Harvard University. The remainder of his botanical library was bequeathed to the Ohio State University then called the Agricultural and Mechanical College. His microscopes were given to Starling Medical College. Of this institution he was senior trustee. He was the author of many new species and the plants named for him by other botanists are as follows: