Sori borne on elongated vascular commissures parallel to the midvein or attached to the outer walls of the areolae but facing the midvein Blechnaceae
Coenosori in a continuous or almost continuous line on each side of the midrib covering the vascular commissures, having a membranous indusium opening inwards towards the costa. Veins of the sterile fronds free Blechnum
Sori in 1–2 (rarely 3) rows, rather short or sometimes later confluent, 1 in each areola attached on the inner side of the veinlet or veinlets parallel to the costa (Fig. 23). Veins areolate in the fertile fronds and most of the sterile fronds, rarely free in the latter Doodia