‘Paedomorphosis’ and ‘juvenility’ in secondary xylem: (not such) useful constructs?

Summary In 1962 Carlquist published “A Theory of Paedomorphosis in Dicotyledonous Woods” based on his observations that some species non-tree growth forms such as stem succulents, lianas, woody herbs, and tree rosettes exhibit, their secondary xylem, cellular characteristics more commonly associated with primary xylem. He considered the appearance these characters an expression protracted juvenility, they reflected paedomorphosis. Since then, many others have observed similar suites traits across multiple plant lineages, also characterize insular woodiness, used ‘paedomorphic’ ‘juvenile’ to describe traits. this essay, it is argued use term paedomorphosis should be restricted cases where ancestor/descendant relationships are known or a comparative sense among closely related taxa, retain its significance descriptor evolutionary pattern. Second, growth, therefore not because characteristic only young, pre-reproductive phases but instead persists for life plant. Because both concepts juvenility possess less well-accepted modern meanings differ important ways from Carlquist’s terms, different approach suggested focuses functional suit traits, addition characteristics.