Anatomy and Histology of the Eureka Lemon

In Eureka lemon the succession of the whorls of the flower parts is acropetal. The nectary or gynoecial disk originates after the carpels. 2. The courses of the vascular bundles and the general histological features of the floral parts are described. 3. The gynoecium is considered a whorl of carpels around the apex of the receptacle which extends past the level of the placenta. 4. Development of the fruit involves a period of cell multiplication throughout the ovary, followed by one of cell differentiation. Differentiation in the pericarp produces three zones: (a) an outer exocarp which is compact and contains oil glands, the flavido; (b) the mesocarp which is spongy and becomes most highly developed close to the inner pericarp, the albido; (c) the inner pericarp which is compact and from which the juice sacs diverge. 5. Primordia of juice sacs appear just before opening of the flower and occur on the adaxial surface of each carpel. After the juice sacs grow across the locules, a portion of each enlarges greatly in diameter. Cells in the center of these areas contain oil and are extremely delicate. Spaces containing gelatinized material in the juice sacs are considered incidental to high turgor and not to action comparable to gland formation. 6. Separation of the sectors of the pulp from one another and from the rind and core is made possible by cell separation and the formation of a spongy area in the tissue adjacent to the adaxial surfaces of the carpels.