ARCHITECTURE OF CAULIFLORY IN THE GENUS CERCIS (FABACEAE, CAESALPINIOIDEAE)

Cercis is a genus with a geographically disjunct distribution in North America, southern Europe, and eastern Asia. The architecture of cauli flory (flowering from the lower branch and trunk areas of woody plants ) was examined in 10 taxa, including 9 of the 11 recognized species in the genus Cercis. In each taxon, a linear series of first-order buds (distinguished as 1) was formed in the axils of vegetative leaves befo re shoot elongation ceased. The first-order bud developed into either a vegetative shoot or more frequently into an inflorescence. Infloresc ences matured and then abscised. Second-order and higher order buds we re produced in the axils of the basal bud scales of abscised infloresc ences. In addition, vegetative shoots that were from first- or higher order buds produced first order buds (distinguished as 1') in their le af axils. Buds from the axils of the basalmost leaves of these vegetat ive shoots, together with higher order buds from the parent shoot, per petuated the cauliflorous condition in all taxa studied. Since caulifl ory was present and since the architecture of cauliflory was similar i n all taxa studied, regardless of geographic distribution, cauliflory probably arose only once in Cercis, before the genus radiated from its site of origin.