The tree of Salisburia adiantifolia, the Maiden Hair or Gingko tree, which has fruited on the grounds of Charles Wister, in Germantown, the past few years, has been carefully watched this year, without discovering any male catkins, and it is still a question how the female flowers get fertilized. There is a tree wholly male, profusely bearing catkins, on the grounds of Mr. John Haines, half a mile east; but it seems scarcely credible that the wind should always blow exactly from the east, to carry this pollen to the Wister tree at just this time every year. There is yet something to learn, evidently, about the behavior of this singular Japan tree. Like all the yew family to which it belongs, some trees are wholly male, some wholly female, and others with both sexes on the one plant.