A, Cyatheaecea: Leaf-segment of Dicksonia antarctica bearing marginal sori with 2-lipped indusia. B, Dennstaedtiaceae: Histiopteris incisa. Portion of a leaf-segment with marginal sori, indusia opening inwards, slightly anastomosing veins. C, Lindsaeaceae: Pinna of Lindsaea linearis with and almost marginal linear sorus, the indusium opening outwards; junction of pinna with main rhachis hidden. D, Adiantaceae: Pinnule of Adiantum aethiopicum with marginal sori and reniform indusia, the venation flabellate.
