The DNA content of nuclei in the embryo of dry seeds ofPinus pineaandLactuca sativawas determined by means of a Deeley type cytophotometer. It was found that in the root apex, shoot apex and cotyledon inPinusand in the root apex and cotyledon inLactucaall nuclei measured were 2C. Only in the root apex of one embryo (probably an immature seed) ofLactucawere both 2C and 4C nuclei found.