Paeoniaceae
YASIN J. NASIR
National Herbarium, Agricultural Research Council,
Islamabad.
Perennial herbs or shrubs with alternate, exstipulate leaves. Leaves 1-3-ternate. Flowers solitary, showy, regular, bisexual. Calyx of 5 free sepals, persistent. Corolla of 5(-10) free petals, Stamens many; anthers extrorse. Carpels 2-5 or 8, apocarpous on a fleshy disc. Fruit consisting of a cluster of (1-)2-8 follicles. Seeds several, large.
A monotypic family with c. 33 species in Asia, Europe and temperate N. America.
Differs from Ranunculaceae in the following characters:
1. Morphological: Extrorse dehiscence of the anthers, the presence of a fleshy disc, the large follicles and arillate seeds.
2. Anatomical: Xylem vessels with scalariform plates (not simple perforations), also the xylem in the stem is not concave or v-shaped but it is rather flat. Large chromosomes of a type not found in Ranunculaceae.
Acknowledgements: We are grateful to the United States Department of Agriculture for financing this research under P.L. 480 and to Mr. I.C. Hedge of the Royal Botanic Garden, Edinburgh for going through the manuscript.
