The paper reports meiotic studies on 50 populations comprising 12 species belonging to 5 genera of Caryophyllaceae from the Western Himalayas. The chromosome numbers in Arenaria kashmirica (n=20), Silene conoidea (n=20), S. edgeworthii (n=12 and n=24), S. moorcroftiana (n=24), S. nepalensis (n=12), Stellaria media (n=13), S. monosperma (n=13) and S. semivestita (n=13) are reported for the first time. The chromosome numbers in Lychnis coronaria (n=12) and Silene vulgaris (n=24) are given for the first time from India, along with Gypsophilla ceratioides (n=15) from the Western Himalayas. The course of meiosis varies from normal to abnormal in different populations of Silene conoidea, S. edgeworthii, S. vulgaris, Stellaria media, S. monosperma and S. semivestita. The course of meiosis was abnormal in all studied populations of Lychnis coronaria. Abnormal microsporogenesis (cytomixis, chromosomal stickiness, unoriented bivalents, formation of laggards and bridges) led to reduced pollen fertility and differences in pollen grain size.

In this study, female gametophytes of Silene muradica, which is a gynodioecious species, were examined histologically. Buds and blossoms of S. muradica were used as the research material. They were collected in the Sivas province (Turkey) in July 2019, and fixed with ethanol:acetic acid solution (3:1, v/v). Flower parts were dissected under a stereo microscope. They were dehydrated in rising alcohol series and then embedded in Historesin. The sections were taken by a rotary microtome and stained with 0.5% Toluidine blue O. The ovary of S. muradica has three carpels and a single chamber, the ovules are arranged on a central column. The mature ovule is of the campylotropous type, crassinucellate and bitegmig. The megaspore mother cell undergoes regular meiotic division and forms a linear megaspore tetrad after meiosis. The development of the embryo sac is monosporic. The chalazal megaspore is functional and the others degenerate. The mature embryo sac is eight-nucleated and of the Polygonum type. The synergid cells and the egg cell are completely surrounded by the cell wall. Antipodal cells are temporary cells, which degenerate immediately after fertilization. Before fertilization, polar nuclei are fused in the central cell and form the secondary nucleus. The endosperm development is of the nuclear type. Nucellar tissue is permanent and forms perisperm in mature seeds. The embryo development is of the Caryophyllad type. In this study, the development of the female gametophyte of S. muradica, which was determined to be a gynodioecious species, was reported for the first time.