Each fertile pinnule bore six, or rarely seven fusiform microsporangia, described as bilocular: not improbably each may represent a synangium.
On the other hand, a polyp on the main stem may form a second bud which, instead of forming a pinnule by uniserial budding, produces by biserial budding a branch, from which pinnules arise as from the main stem (fig.
F, foundersecond bud, which usually polyp; I, 2, 3, succession of polyps forms a side branch or pinnule budded from the founder.
F, uniserial pinnules arise founder; 1 -8, main axis formed by biserial as from the main stem budding from founder; a-e, pinnule formed - type of Aglaophenia by uniserial budding from founder; a l -d i, (fig.
Ct, Swollen pinnule forming, a s, Sense organ.