Studies into abstract properties of individuals. IV. Emergence In different aged needle primordia of Douglas fir.

Young, middle aged and older Douglas fir needle primordia, as determined by distance from the apical meristem, were measured and analyzed to compare levels and patterns of emergence related to development time. Emergence was seen in the differently aged needle primordia, generally most noticeable in the oldest and the least apparent in the youngest. There was also a negative relationship between variation in size and degree of emergence, and a positive one with variation in organization. The increasing level of emergence that appears with age can be related to the continual expression of information and the concomitant increase in complexity that marks ontogeny and is the result of diverging developmental trajectories. The histogenetic events seen in ontogeny can be interpreted as 'clocks' generating local time through the interactions among cells and tissues that make up the needle primordia. Emergent properties are manifested through the local events that mark ontogeny, and also through the expression of phylogenetic information, or the local expression of global (historical) levels of organization.