Potentilla
Content
Description
Herbs of different habit, rarely shrubs.
Leaves compound (palmate, pinnate, trifoliolate, rarely unifoliolate).
Stipules adnate to the petiole, herbaceous or membranous.
Flowers solitary and axillary or opposite the leaves, or in cymose or thyrsoid inflorescences, 5-(4-6)-merous, bisexual.
Sepals valvate, usually entire.
Petals entire, yellow or white, rarely red or purple.
Stamens many (up to c. 30) to few.
Fruits free, dry achenes or mesocarp slightly fleshy, surrounded by persistent epicalyx and calyx, torus rarely enlarging and becoming spongy to fleshy.
Seed with thin testa.
Distribution
Asia-Tropical: New Guinea present, northern hemisphere present, worldwide present
About 250-400 species, worldwide but mainly in the Northern hemisphere. In Malesia 18 species with a centre of diversity (14 species) in New Guinea.
Notes
Sometimes parts of the genus as delimited here, are regarded as separate genera, e.g. Argentina (to which several Malesian species probably would have to be referred if the genus were accepted), Comarum (not in Malesia), and Duchesnea. The latter two differ from Potentilla in developing a swollen, spongy torus. It seems a certainty to me that this is a polyphyletically acquired character state. Separation and recognition of the two genera leads to a paraphyletic genus Potentilla. Also for Fragaria, and for the same reasons, the combination with Potentilla could be considered. This would, however, either necessitate hundreds of new combinations in Fragaria, or in the case of conservation, new and unfamiliar names for the stawberries. (See also Kalkman 1968).