Anatomy of Flower of Some Polygonaceae*

The anatomy of flower of 33 species (11 spp. of Polygonum, 7 spp. of Persicaria, 7 spp. of Rumex, 2 spp. each of Rheum and Oxyria and one sp. each ofAntigonon, Muehlenbeckia, Bilderdykia and Fagopyrum) has been studied.

The flowers are terra-to hexamerous and tri-to penta cyclic. The number of tepals may be 4 (Oxyria, Polygonum lanigerum, P. orientale and P. alatum) or 5 (Polygonum spp. Fagopyrum, Muehlenbeckia, Bilderdykia and Antigonon) or 6 (Rheum and Rumex). They are usually arrange in one whorl but in tetramerous flowers of Polygonum as also in Rheum and Rumex they are arranged in two whorls.

The tepals are usually single trace structures but in Oxyria the inner tepals are 3.-traced. In Antigonon they may be 2 or 3-traced structures, hi Polygonum serrulatum, P. plebejum and Persicaria amplexicaulis the alternate tepal is 2 trace. It is throught that the two traced condition has perhaps resulted by the fusion of two tepals. The tepals and stamens constitute a floral tube which separates from the ovary after the departure of carpellary vasculature. The tepals separate from the stamens at a higher level. The tepals traces usually arise independently, hi most of the species of Polygonum, Persicaria, Fagopyrum, Bilderdykia and Muehlenbeckia the five traces arise in 3+2 manner. \n Antigonon the adjacent tepal laterals usually arise conjointly. In some species of Polygonum and Persicaria the tepal bundle arise conjointly with stamen bundle.

The number of stamens ranges from 5–9. they may arise in one or two whorls. In most of the species ofPolygonum, Persicaria and Fagopyrum there are eight stamens arranged in 5+3 manner. InRheum, the stamens are arranged in 6+3 manner, hi Muehlenbeckia and Bilderdykia all the eight stamens arise in one whorl but in Antigonon they get arranged in 5+3 manner. In Oxyria and Rumex there are six stamens which appear in one whorl. Reduction in the number of stamens from three to none has been observed in the inner whorl of some species of Polygonum. Reduction in the number of stamens in the outer whorl is also not uncommon. While in most of the species studied the stamens show adelphous condition at the base, in Antigonon they are basally connate and organise into a staminal tube. The staminal bundle usually arises independently but in Rumex the supply of a staminal pair arises conjointly with the dorsal. The staminal bundle is concentric and usually remains unbranched but in two species of Rumex it branches into two in the connective region.

The gynoecium is usually tricarpellary but in Oxyria and some species of Polygonum it is bicarpellary with a single basal ovule. The vasculature of gynoecium comprises three or two dorsal bundles which, after their departure leave behind a ventral plexus. This plexus breaks up into three or two ventral strands and furnish an ovular trace. In some species of Polygonum and Rumex the ventrals do not become distinct. The ovular trace supplies the single ovule where it is completely used up. The dorsals continue in the style and terminate in the carinal stigma. The ventrals may run upto different heights in the ovary wall.