A 3 hr. period treatment with a 0.2% aqueous solution of colchicine was given to one week old seedlings of seven inbred lines of wheat (Triticum aestivum L.) plants. Comparisons were made in the CT1 generation between the untreated controls (2x) and colchicine treated plants (C2x) for variation of leaf mesophyll cell size and chloroplast number. Differences were 4ound in that the cell section area and the number of chloroplasts per cell in all the seven lines investigated were significantly greater in the C2x selection compared with the 2x controls using coded determination. Heritable differences were found such that the cell selection areas and the numbers of chloroplasts per cell were significantly greater in the C2x treatment in all the lines. In each case there was an enhancement of chloroplast number independent of the variation in cell size.