A century after an imported pathogenic fungus from Asia decimated billions of American chestnut trees (Castanea dentata) in the eastern United States, what remains of these once magnificent trees are the small root sprouts, easily found in forests if you keep an eye out for the distinctive toothed leaves. These sapling-sized trees grow some ten to twenty feet, usually without ever flowering, and then succumb inevitably to disease, only to renew the suckering operation all over again.
Although far from majestic, one of the Arnold Arboretum’s American chestnut trees put on a pretty good flower show last week. The long catkins of pollen-producing flowers are what make for the spectacular floral display (left and upper right images; C. dentata 24-80*A). I could not find any female flowers on the American chestnut trees this year, but a close look at C. mollissima (Chinese chestnut; lower right; 13200*A) shows a set (inflorescence) of three female flowers with their long stigmas waiting to receive pollen. Beyond American and Chinese chestnuts, the Arboretum’s collection includes the Allegheny chinquapin (C. pumila; also susceptible to blight), the Ozark chinquapin (C. ozarkensis), Japanese chestnut (C. crenata), and Spanish chestnut (C. sativa).
American chestnuts are far from extinct in the wild. However, until a proper combination of mutations produces a blight resistant tree or an earlier maturing form that flowers before blight takes its toll (but would live on as a diminutive understory tree), the future of the American chestnut remains uncertain.
