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Porella (order Jungermanniales) A genus of leafy liverworts, including P. platyphylla, which is a robust, conspicuous species which can form fairly extensive patches. The stems are 2- or 3-pinnately branched and up to 8 cm long. The leaves overlap closely in the incubous arrangement. There are 2 lateral rows of leaves; each leaf is divided into 2 parts: a broad, ovate part, and a much smaller, narrower lobe which looks like a separate leaf. There is also a conspicuous row of leaves on the under-surface, so that when the plant is viewed from below it appears to have 5 ranks of leaves. The leaves on the under-surface are broad and rounded with narrowly recurved margins. It is found, often abundantly, on shaded banks, tree roots, etc., mainly in calcareous districts.