There will be an international convention of botanists and horticulturists at St. Petersburg, to celebrate the first quarter century of its existence, to extend from the 5th to the 16th (17th to 28th, we believe, of our calendar) of May, 1883. The Grand Duke Nicholas has taken the affair under his patronage. Dr. Regel asks us to invite the presence of such American horticulturists and botanists as can make it convenient to attend personally, or to send papers for the convention or specimens for exhibition, where personal attendance is not possible. French will be the official language of the congress, but papers or correspondence may be in the writers native language, where French is unknown to them. Twenty to thirty minutes will be the limit accorded to each paper.