Crown Architecture of Two Understory Palm Species of the Genus Licuala in a Tropical Rain Forest
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The crown architecture of two understory palms, Licuala arbuscula and L. bintulensis, was studied in a tropical lowland rain forest in West Kalimantan, Indonesia. The two species had only stagnant stems and developed a hemispherical crown formed with long petioles and fan-shaped leaf blades. Petioles at leaf emergence stood vertically, while petioles of older leaves were bent downward. Leaves were concentrated on the top of the crown. The leaf blade deflected ca. 40° from the horizon to the inside of crown when the petiole stood vertically. Because the divergence angle between the leaf blade and its petiole did not change, the zenith angle of the leaf blade changed with that of the petiole. This divergence angle between leaf blade and petiole allowed the formation of a compact foliage clump with less overlap at the top of the crown, and the horizontal expansion of leaves at the middle of the crown. The size and number of leaves within the crown increased with crown development, and the ratio of the petiole to the leaf blade length increased. This enabled the two palms to extend their assimilative area over the non-photosynthetic supportive part as petioles in the small size stage and to avoid the overcrowding of leaves within a crown with crown development. These results suggest that the two understory palms develop crowns as to avoid self-shading through adjusting the divergence angle between leaf blade and petiole and through the allometry between them.
- Plant species biology
Plant species biology 12(1), 35-41, 1997-04-01
Society for the Study of Species Biology