Figure 4.

Axes are log-transformed. Each point represents a segment of an individual sporophyte. (a) The developmental scaling relationship between SE diameter and stipe diameter in six kelp species. Four of the six species display significant relationships: for M. pyrifera, m = 0.87; for N. luetkeana, m = 0.30; P. californica and L. setchellii are indistinguishable with m = 0.20 and 0.15, respectively. (b) The packing rule in kelp. Average SE diameter is plotted as a function of conduit packing (number of SE per µm²); only M. pyrifera displays a significant relationship, m = −0.53). (c) The allometry of SE size and supported metabolic tissue. Average SE diameter is plotted as a function of cumulative blade area supported by each segment. Three species scale: A. marginata, m = 0.11; L. setchellii and M. pyrifera are statistically indistinguishable with m = 0.23 and 0.19, respectively. (Online version in colour.)