LE AF DEVELOPMENT IN CURIO MUIRII (L. BOLUS) VAN JAARSV. (ASTERACEAE - SENECIONEAE)

Abstract

Curio muirii is the only species in the genus with bifacial leaves, making it crucial for understanding leaf evolution in this group. Leaf development can be divided into three stages: initiation, bizonal primordium, and intercalary growth. The developing leaves of C. muirii are bifacial and resemble those of other angiosperms from inception to the end of the bizonal primordium stage. However, as in monocots, the primary vascular bundles differentiate at the end of the bizonal primordium stage. The unifacial forerunner tip, which is recognized for Curio species but unknown for other eudicots, is the rst discernible part of the de nitive leaf. The leaf blade and petiole in C. muirii are distinctive in their biphasic development during the intercalary stage. The petiole grows faster than the leaf blade during the rst phase. During the second phase, the lamina overcomes the petiole in terms of length. In the developing leaf blade, the marginal meristem was not found. Adaxial meristem activity causes the leaf base to thicken unevenly during intercalary growth and envelopes the younger leaf primordium in the resultant depression.