The effects of plant age and infestation level of twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), on visible plant damage, and the effect of plant age on spider mite population growth on impatiens, Impatiens wallerana Hook.f. (Ericales: Balsaminaceae), were determined by
Swelling of and cytoplasmic streaming within the grain, germination pore expansion, and pollen tube emergence, in that order, constitute the normal germination pattern of Impatiens holstii pollen grains. This normal sequence of events becomes manifest when the pollen grains are placed on water-agar,