Foliar Indicators of Age Foliar Indicators of Age in Louisiana Native in Louisiana Native Dwarf Palmetto PlantsDwarf Palmetto Plants

Jim Wandersee, Ph.D.Jim Wandersee, Ph.D.William LeBlanc Alumni Association Professor of Biology EducationWilliam LeBlanc Alumni Association Professor of Biology Education

LSU Department of Curriculum & Instruction &LSU Department of Curriculum & Instruction &

LSU AgCtr Burden Research CenterLSU AgCtr Burden Research Center

IntroductionIntroduction

Dwarf Palmetto (Dwarf Palmetto (Sabal minorSabal minor) is a native ) is a native Louisiana plant Louisiana plant

Understory palm found in the Southeast Understory palm found in the Southeast in swamp forests and on floodplainsin swamp forests and on floodplains

Slow growing to hundreds of years of ageSlow growing to hundreds of years of age First described in 1691 by Le Clercq in First described in 1691 by Le Clercq in

an account of La Salle’s explorations of an account of La Salle’s explorations of the Mississippi River the Mississippi River

Dwarf PalmettoDwarf Palmetto

Botanical Botanical ClassificationClassification

Family: PalmaeFamily: Palmae Genus: Genus: SabalSabal Specific epithet: Specific epithet:

minorminor

The Palm FamilyThe Palm Family(Palmae)(Palmae)

Found in sub-tropics and tropicsFound in sub-tropics and tropics Third-largest monocot familyThird-largest monocot family Contains >2,700 species in >200 generaContains >2,700 species in >200 genera Greatest diversity in SE Asia & Greatest diversity in SE Asia &

Malaysia, Central America, African Malaysia, Central America, African Congo region, and N. Madagascar (Uhl & Congo region, and N. Madagascar (Uhl & Dransfield, 1987)Dransfield, 1987)

Range: Distribution of Range: Distribution of Sabal minorSabal minor

Coastal plains of the Coastal plains of the South Atlantic Seaboard South Atlantic Seaboard and the states bordering and the states bordering the Gulf of Mexicothe Gulf of Mexico

Louisiana is the ONLY Louisiana is the ONLY state to be completely state to be completely included in its rangeincluded in its range

States partially within its States partially within its range are NC, SC, GA, range are NC, SC, GA, FL, AL, MS, & TXFL, AL, MS, & TX

S. MinorS. Minor Inflorescence Inflorescence Structure & FruitStructure & Fruit

Flowering season: mid-June to July

Sabal minorSabal minor data recorded in the botanical data recorded in the botanical literature suggest:literature suggest:

Height MINIMA: ~40 centimeters (mature)Height MINIMA: ~40 centimeters (mature) Height MAXIMA: ~5.8 meters (mature)Height MAXIMA: ~5.8 meters (mature) As a rule of thumb, height increases from east As a rule of thumb, height increases from east

to west (e.g., Panhandle of Florida to West to west (e.g., Panhandle of Florida to West Texas).Texas).

Caulescent populations have not been Caulescent populations have not been observed in the eastern half of its range observed in the eastern half of its range (Ramp, 1989).(Ramp, 1989).

Variablity in Variablity in StatureStature

Research Program GoalsResearch Program Goals

To improve both To improve both scientific scientific understanding and understanding and public understanding public understanding of one of Louisiana’s of one of Louisiana’s most widespread and most widespread and “signature” native “signature” native plant species, plant species, Sabal Sabal minor.minor.

Research Target: Phase IResearch Target: Phase I

To find the simplest way of estimating To find the simplest way of estimating the age of individual the age of individual Sabal minorSabal minor plants—by investigating the predictive plants—by investigating the predictive value of selected foliar variables that value of selected foliar variables that are supported by a review of relevant are supported by a review of relevant research literature in plant ecology and research literature in plant ecology and in horticulture.in horticulture.

Research PlotsResearch Plots Phase I: Full Sun SpecimensPhase I: Full Sun Specimens Will yield a conservative age estimateWill yield a conservative age estimate Plot #1: 3-acre Barton arboretum area of BRCPlot #1: 3-acre Barton arboretum area of BRC ~40 individuals of varying pre-reproductive age~40 individuals of varying pre-reproductive age

Phase II: Forest Understory SpecimensPhase II: Forest Understory Specimens In full range of stages [#1-#12] of developmentIn full range of stages [#1-#12] of development 3 native population plots within BRC’s 100-acre 3 native population plots within BRC’s 100-acre

forestforest

Methods Methods Foliar Variables under study:Foliar Variables under study:Leaf surface area for largest leafLeaf surface area for largest leafMaximum leaf thickness for largest leafMaximum leaf thickness for largest leafLeaf oven dry mass (estimated by Leaf oven dry mass (estimated by

regression equation via petiole blade-regression equation via petiole blade-basal width for largest leaf)basal width for largest leaf)

Total number of leaves per plantTotal number of leaves per plantTotal number of leaf scars per Total number of leaf scars per plant, plus (see next slide)plant, plus (see next slide)

Methods continued Methods continued Foliar Variables under study:Foliar Variables under study:Munsell Plant Tissue Color Chart ratings Munsell Plant Tissue Color Chart ratings

for the largest and smallest leavesfor the largest and smallest leavesLeaf nutrient analysis of 21 elements via Leaf nutrient analysis of 21 elements via

ICP spectroscopy for largest and ICP spectroscopy for largest and smallest leavessmallest leaves

These variables will be correlated to These variables will be correlated to historically established, age-benchmark historically established, age-benchmark specimens, and to pre- and post-specimens, and to pre- and post-reproductive features described by Ramp reproductive features described by Ramp (1989).(1989).

Researcher MembershipsResearcher Memberships American Association for the American Association for the

Advancement of ScienceAdvancement of Science Botanical Society of AmericaBotanical Society of America Crosby ArboretumCrosby Arboretum LSU 15LSU 15º Laboratoryº Laboratory National Association of Biology National Association of Biology

TeachersTeachers National Tropical Botanic National Tropical Botanic

GardenGarden International Palm SocietyInternational Palm Society Royal Horticultural SocietyRoyal Horticultural Society