September 26, Connecticut River, Hadley
Green involucre enclosing a single floret is ovoid or pear-shaped, featuring a stout conical beak. The beak is 5-10 mm long, with opening at summit, through which style branches emerge. While the fruit is maturing, its involucre hardens and, together with the inside achene, forms a bur (left). Both fruits here undersized, appearing abortive.