Structure and Development of Leaves in Carludovica Palmata (Cyclanthaceae) With Reference to Other Cyclanthaceae and Palmae

Abstract

The adult leaf of Carludovica palmata consists of a plicate lamina, adaxial hastula, petiole, and sheath. The leaf is unusual in the angiosperms because about two‐thirds of the apical meristem is utilized in its initiation. The adult leaf requires about 4–5 plastochrons to mature. Shortly after its initiation the adult leaf and apical meristem collectively appear pyramid‐shaped and various parts of the mature adult leaf may be traced back to particular portions of the pyramid. Plications develop by differential growth within the lamina, not by splitting of leaf tissue. Quantitative studies indicate that certain regions of the developing adult leaf elongate more rapidly or slowly than other regions depending upon the stage of leaf development. The adult leaf of C. palmata develops differently from those of previously studied palms in various ways. It therefore appears less justifiable to consider the superficial similarity between the adult leaves of various Cyclanthaceae (particularly those of Carludovica sensu strictu) and those of fan palms as evidence of especial affinity between the Cyclanthaceae and Palmae. Juvenile leaves of C. palmata differ from adult leaves both in their mode of origin and appearance at maturity. The juvenile leaf appears homologous to the entire adult leaf.

Proposed new realignments in the angiosperms

“…Bot. 3(1) 1983 (1972), Moore & Uhl (1973), Wilder (1976Wilder ( , 1981 and Tomlinson (1979) when they have stressed the great differences among these three groups. The derived woodiness, plicate leaves, and other similarities are surely convergences.…”

Morphology and symmetry of the vegetative parts of Smilax auriculata (Smilacaceae)

“…By comparison, Wilder (1976Wilder ( , 1977aWilder ( , 1977bWilder ( , 1981aWilder ( , 1981b) observed a different manifestation of mirrorimage symmetry in certain species of Cyclanthaceae (Monocotyledoneae). In those cases, on a shoot or a portion of shoot with clockwise phyllotaxy, all first-order vegetative lateral buds exhibited counterclockwise phyllotaxy, and vice versa.…”

A fossil coryphoid palm from the Paleocene of western Canada

“…Cyclanths can be differentiated from palmate palm leaves (fan palms) in key ways seen on the fossil: 1) in cyclanths, the veins extend to the end of the leaf, whereas in palm leaves, the veins end at the margins; 2) cyclanths always have more than one midrib or costa per leaf (bicostate in Cyclanthus, tricostate in Carludovica palmata), whereas palms always have a single midrib (Wilder, 1976), i.e. the single costa seen in Sabalites geneseensis.…”