InConvolvulus pluricaulis Chois. two forms (2n=18, 36) along with one colchicine-autotetraploid have been investigated morphologically and cytologically. The diploid regularly formed 9II although in the “off-season” plants certain irregularities were observed including formation of unreduced pollen grains. The natural tetraploid and the colchicine-autotetraploid had mean frequencies of configurations of 1.56IV+14.04II+1.48I and 2.95IV+0.56III+11,43II+0.8I, respectively. The mode of chromosome association in the two types of tetraploids was comparable. A comparison of the morphological characters of the two tetraploid types, further, suggested close similarity. In addition they were indistinguishable from the diploid from except being gigas. From these data it is inferred that the natural tetraploid presumably arose as a result of direct duplication of the diploid form, through the chance fusion of unreduced spores. The lower quadrivalent frequency of the natural polyploid is ascribed to a gradual shift towards bivalent association accompanying natural selection for fertility. The taxonomic status of the two forms (2x, 4x) is discussed and the varietal status accorded to the tetraploid form is supported.