Our understanding of phyllotaxis is still largely based on surgical and pha
rmacological experiments carried out before 1970. Recent experiments implic
ate the plant hormone auxin in the regulation of phyllotaxis. A recent pape
r shows how the polar auxin transport mutant, pin 1-1, which fails to make
flowers, affects the expression of well known meristem genes. This work ope
ns the door for the genetic analysis of phyllotaxis.