All of the following statements are correct except:
(1) The proximal end of the filament is attached to the thalamus or the petal of the flower.
(2) The anther is a four-sided structure consisting of four microsporangia, two in each lobe.
(3) The number and length of stamens are variable in flowers of different species.
(4) In a longitudinal section, a typical microsporangium appears near circular in outline.