Dichasium. Kind of inflorescence.

Dichlamydeous.
Having too whorls on the Perianth segments of flowers.

Diochogamy. The maturation of anthers and ovules in a flower at different times.

Didelphia. Marsupialia.

Didymous.
Of plant structures) formed of two similar parts which are attached at some point.

Diffusion Pressure Deficit.  Net capacity of plant cell to absorb water; can be expressed by the equation.

DPD = (P1-Po)T
Where P1 is osmotic pressure of vacuole solution, P0 that of solution outside cell and T the turgor pressure.

Digenea. A subclass or order of trematodes containing the liver Flukes.

Digestion. Breakdown of complex foodstuffs by enzymes to simpler compounds which can be incorporated into metabolism. In many animals it is extracellular, i.e. enzymes are secreted into gut cavity, in which digestion takes palce, e.g. vertebrates arthropods; in others it is wholly or partly intracellular, the cell of the gut phagocytosing solid food particles, e.g. coelenterates, lamellibranches.

Digit. Finger or toe of pentadactyl limb. Contains phalanges.

Digitigrade.
Walking on toes, not on whole foot; i.e on ventral surface of digits only e.g. cat, dog.