Abstract: A blank (1) of stiff yet foldable sheet material erectable into a container base (3), comprising a rectangular bottom panel (10), a pair of side wall panel means foldably connected to sides of the bottom panel and provided with end flaps (19,20; 21,22), a pair of end wall panel means each comprising a first end wall panel (27,28) foldably connected to an associated end of the bottom wall panel (1) so as to be foldable upwardly therefrom and a second end wall panel (31,32) foldably connected to the first end wall panel, and foldable gusset means (43-46) at each corner of the bottom panel connecting opposite ends of each side wall panel means to opposite ones of said end wall panel means. In the erected container base the two end flaps (19,20; 21,22) are folded against the associated first end wall panel (27,28) and the second end wall panel (31,32) of each end wall panel means is folded over the underlying end flaps.