The family Cucurbitaceae has been of vital importance in food economics of many tropical countries since the dawn of human civilization. About 90 genera comprising 750 species have been recorded from the world (Whitaker and Davis 1962). Seventeen percent of the total Cucurbits (Chakaravarty 1959) with 108 species belonging to 34 genera grow in India, which has been recognized as one of the three primary centres of origin of the cultivated Cucurbits (Vavilov 1931). A perusal of past literature in the genus Cucumis shows that cytological studies were confined to a few species only. Studies on meiotic analysis are not comprehensive barring few species on which workers like Singh (1972) Singh and Roy (1975) and Dane and Tsuchiya (1979) gave some informations regarding meiotic behaviour.In the present investigation as many as twenty four species and varieties have been studied meiotically to trace out the phylogenetic relationship among them. Material and methodsCucumis species and varieties used in the present investigation were obtained from different sources. A list of all available species along with their details has been presented in Table 1. Seeds were sown in pots and plots in rainy season. For meiotic analysis, young floral buds were fixed in acetic alcohol (1:3) with a drop of 5% ferric chloride. The anthers were dissected out from floral buds and squashed in 1% acetocarmine. Gentle tapping of the cover glass and some pres sure on the slide after warming it over spirit lamp facilitated the separation of chromosomes. Slides sealed by paraffin wax were used for detailed study and photomicrography.Slides were made permanent by using n-butyl alcohol series (Celarier 1956). ObservationsMeiotic analysis in twenty four species of Cucumis was done. Normal meiosis was observed in twenty diploid species. Four species were found to be natural polyploids (4x). A detailed summary of meiotic analysis of diploid and polyploid 1 Cytogenetist , Groundnut Improvement Programme, ICRISAT,

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Sclerospora graminicola (Sacc.) Schroet., the obligate pathlogen causing downy mildew (green-ear) of pearl millet (Pennisetum typhoides Stapf. and Hubb.) has been successfully cultured for the first time on a known semisynthetic mediumn with no evident loss of fructifications. Sclerospora graminicola was first grown on host callus tissue and subsequently on a modification of White's basal medium that contained casein hydrolyzate (Oxoid). 2,4-dichlorophenoxyacetic acid, and kinetin.

Tissue cultures were established from stem explants of Calotropis procera, a hydrocarbon yielding desert shrub on Murashige and Skoog's medium supplemented with 1.5 mg. 1(-01) 2,4-D + 0.5 mg.1(-1) kinetin and polyvinylpyrrolidone. Laticifer cells were not present in young callus but were observed after 4 weeks of callus growth when examined histochemically. These young laticifers were detected in the 5th week of culture and were distinguished from surrounding cells by the presence of characteristic cytoplasm and thin walls. A group of cells with extensive branching was developed after 8 weeks of growth of the callus cultures. These cells were thick walled and contained latex particles in coagulated masses. Positive Liebermann-Burchard test proved the presence of terpenoids in these laticifers.