The Inflorescence ofEUCALYPTUSand its Interpretation. —The inflorescence in the genus Eucalyptus is apparently quite variable. Therefore, in the floral organisation morphologists have identified four different types: 1) solitary flowers; 2) umbel; 3) panicle; 4) corymb (fig. 1). The inflorescence called umbel may also appear under the following different aspects: a 3-flowered umbel (which is to be considered as a cyme); an umbel with pedicellate flowers; an umbel with sessile flowers (which is therefore a head) (fig. 2). Blakefirst (1953) thought, that the 3-flowered umbel was a simple dichasium, and he pointed out that the other types of inflorescences were branched and highly modified dichasia (figs. 4–2). This hypothesis has been confirmed and enlarged byPryor(1954)and Carr&Carr(1959) after a more detailed study of the developmental morphology of the inflorescence and mainly of the characters of bracts (figs. 10–2). Their studies proved that all the inflorescences (umbels, heads, panicles, etc.) are modified dichasia; even the solitary flower is a dichasium reduced to the terminal flower of the main axis (fig. 12). Therefore the dichasium, according toBlake,is the fundamental structure of all the inflorescences of Eucalyptus.