1. Foliar Indicators of Age in Louisiana Native Dwarf Palmetto Plants
Jim Wandersee, Ph.D.
William LeBlanc Alumni Association Professor of Biology Education
LSU Department of Curriculum & Instruction &
LSU AgCtr Burden Research Center

2. Introduction Dwarf Palmetto (Sabal minor) is a native Louisiana plant
Understory palm found in the Southeast in swamp forests and on floodplains
Slow growing to hundreds of years of age
First described in 1691 by Le Clercq in an account of La Salle’s explorations of the Mississippi River

3. Dwarf Palmetto Botanical Classification Family: Palmae Genus: Sabal
Specific epithet: minor

4. The Palm Family (Palmae)
Found in sub-tropics and tropics
Third-largest monocot family
Contains >2,700 species in >200 genera
Greatest diversity in SE Asia & Malaysia, Central America, African Congo region, and N. Madagascar (Uhl & Dransfield, 1987)

5. Range: Distribution of Sabal minor
Coastal plains of the South Atlantic Seaboard and the states bordering the Gulf of Mexico
Louisiana is the ONLY state to be completely included in its range
States partially within its range are NC, SC, GA, FL, AL, MS, & TX

6. S. Minor Inflorescence Structure & Fruit
Flowering season:
mid-June to July

7. Variablity in Stature
Sabal minor data recorded in the botanical literature suggest:
Height MINIMA: ~40 centimeters (mature)
Height MAXIMA: ~5.8 meters (mature)
As a rule of thumb, height increases from east to west (e.g., Panhandle of Florida to West Texas).
Caulescent populations have not been observed in the eastern half of its range (Ramp, 1989).

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

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

10. Research Plots Phase I: Full Sun Specimens
Will yield a conservative age estimate
Plot #1: 3-acre Barton arboretum area of BRC
~40 individuals of varying pre-reproductive age
Phase II: Forest Understory Specimens
In full range of stages [#1-#12] of development
3 native population plots within BRC’s 100-acre forest

11. Methods Foliar Variables under study:
Leaf surface area for largest leaf
Maximum leaf thickness for largest leaf
Leaf oven dry mass (estimated by regression equation via petiole blade-basal width for largest leaf)
Total number of leaves per plant
Total number of leaf scars per
plant, plus (see next slide)

12. Methods continued Foliar Variables under study:
Munsell Plant Tissue Color Chart ratings for the largest and smallest leaves
Leaf nutrient analysis of 21 elements via ICP spectroscopy for largest and smallest leaves
These variables will be correlated to historically established, age-benchmark specimens, and to pre- and post-reproductive features described by Ramp (1989).

13. Researcher Memberships
American Association for the Advancement of Science
Botanical Society of America
Crosby Arboretum
LSU 15º Laboratory
National Association of Biology Teachers
National Tropical Botanic Garden
International Palm Society
Royal Horticultural Society