Raylessness and paedomorphosis: losses and gains of xylem rays en route from procambium to vascular cambium

Summary A recurring motif of Carlquist’s work is the identification traits typical for primary xylem angiosperms as a whole, but found in secondary certain species. These together make up ‘Carlquistian syndrome’. Convergent occurrence syndrome plants with similar habits suggests its adaptive value. One components — raylessness has received most attention and been regarded result selection favouring stem rigidity. However, how (or Carlquistian general) arises ontogenetically little studied. Here, we report that some resembles same individual, not general observed by Carlquist. Based on literature microslide surveys, identified this prolongation patterns into major clades non-monocot angiosperms, including magnoliids, asterids rosids.