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LEAF DEVELOPMENT AND CROWN GEOMETRY OF TWO IRIARTEOID PALMS
Author(s) -
Rich Paul M.,
Holbrook N. Michele,
Luttinger Nina
Publication year - 1995
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1995.tb12637.x
Subject(s) - crown (dentistry) , biology , interception , botany , leaflet (botany) , palm , horticulture , geometry , mathematics , ecology , medicine , physics , dentistry , quantum mechanics
We examined changes in pinnately compound leaf morphology and crown geometry that occur during height growth of the iriarteoid palms Socratea exorrhiza and Iriartea deltoidea in tropical wet forest of Costa Rica. Although light availability increased with height, the number of leaves per plant was relatively constant. Total leaf area, however, was much larger in taller individuals. Increases in linear dimensions of leaves (length and width) was responsible for less than half of this greater surface area. More important was the transition from a basically dorsiventral display of leaflets in small individuals to a more radial display in taller plants. Production of leaflets in more than one plane resulted in leaves whose surface area was more than twice the horizontally projected area and whose lateral light interception was greatly enhanced. S. exorrhiza , a faster‐growing and more light‐demanding species, undergoes this transformation in leaf morphology at heights between 3 and 6 m; whereas in the slower‐growing and more shade‐tolerant I. deltoidea this occurs at heights between 10 and 20 m. Pinnate leaves, with dense radial packing of leaflets along the rachis, are functionally comparable to branches of dicotyledonous trees and may have been important for the evolution of arborescence in palms.