At the meeting of the Botanical section of the Academy of Natural Sciences, of Philadelphia, on April 9th, Mr. Thomas Meehan referred to his past communications to the Academy showing that in monaecious plants female flowers would remain at rest under a temperature which was sufficient to excite the male flowers to active development. Hence, a few comparatively warm days in winter or early spring would bring the male flowers to maturity, while the female flowers remained to advance only under a higher and more constant temperature* In this manner the explanation was offered why such trees were often barren. The male flowers disappeared before the females opened, and hence the latter were unfertilized. He referred especially to some branches of Corylus Avellana, the English Hazel nut, which he exhibited before the section last spring, in which the male flowers (catkins) were past maturity, the anthers having opened and discharged their pollen, and the catkins crumbling under a light touch; but there were no appearances of action in the female flower buds. There were no nuts on this tree last season. The present season was one of unusually low temperature. There had not been spasmodic warmth enough to bring forward the particularly excitable maple tree blossoms.

The hazel nut had not therefore had its male blossoms brought prematurely forward. He exhibited specimens from the same tree as last season, showing the catkins in a young condition of development, only half the flowers showing their anthers, while the female flower buds had their pretty purple stigmas protruding from nearly all of them. Mr. Meehan remarked that his observations the past few seasons had been so carefully made that he hardly regarded confirmation necessary, but believed the further exhibition of these specimens might at least serve to draw renewed attention to his former communications.