The mode of branch growth was nicely described by S. Carlquist (1974). At the end of the first year, basal lateral buds on the main stem produce side shoots. At the end of the second year, those shoots produce terminal clusters of heads. At the end of the third year, those same side shoots produce new lateral shoots from distal nodes below the heads. Thus, the plants produce shoots from lateral buds both at the base of the stem and from nodes on side shoots below the terminal clusters.
The growth pattern, architecture, and habit of Munzothamnus blairii are not at all similar to those of Stephanomeria guadalupensis Brandegee, an endemic of Guadalupe Island, Mexico, nor to those of S. cichoriacea, which grows in the equable climate of southern coastal California and on off-shore islands. The contrast between M. blairii and those undoubted stephanomerias is noteworthy. That Munzothamnus blairii is best regarded as a monotypic genus is also supported by recent results of DNA sequencing studies (J. Lee et al. 2002). which showed that it is not in the clade of all stephanomerias.
