Development of the Macrogametophyte and Embryo of Daucus carota

1. This paper is concerned with the development of the female gametophyte, the pollen tubes, and the embryo of Daucus carota. 2. A single archesporial cell functions directly as a macrospore mother cell which produces a linear tetrad of macrospores. 3. The macrogametophyte, which arises from the chalazal macrospore, is of the 7-celled type characteristic of most angiosperms. 4. The presence of a cellulose filiform apparatus was demonstrated by microchemical tests. 5. The structure and path of the pollen tubes were investigated. Tubes were found to grow intercellularly down through the conducting tissue of the style to its base, and then superficially along a groove leading to a canal communicating with each locule. Tubes growing down one style may enter the locule immediately below or grow through the transverse canal and into the other locule. 6. A filamentous 8-celled embryo is usually formed before longitudinal divisions occur. The three cells farthest from the micropyle give rise to all of the embryo ...