Phanerosorus

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Phanerosorus

Description

Leaves pendulous, pinnately compound, pinnately lobed at apex;

Distribution

Asia-Tropical:
Two species, both in Malesia.

Morphology

The leaf morphology of Phanerosorus is similar to that of the small leaf of young Matonia plants , in particular in that the pinna-segments of young Matonia plants are unequally forked, as are the pinnules of Phanerosorus. The remarkable difference in leaf morphology of the genera is suggested to be due to heterochrony (paedomorphosis).

There are two kinds of leaf buds. One is a terminal bud at the apex of a pinna, and the other is an adventitious bud near the base of bud-derived secondary pinnules or leaflets. Leaf buds may develop into leaflets ranging from simple pinnules to large leaf-like leaflets; thus the leaves can grow indeterminately.

Cytology

According to Walker & Jermy, n = 25 .

Citation

Copel., Gen. Fil. 1947: 172
K.U. Kramer - in Kubitzki (ed.), Fam. & Gen. Vasc. Pl. 1. 1990: f. 95