Serenoa repens (W. Bartram) Small

Standardized Common Name: Saw Palmetto

Family: Arecaceae (Palmae)

Taxonomy: Serenoa includes only one species, S. repens, which is endemic to the warmest parts of the southeastern United States and especially common in Florida. This species has been placed in several different genera, as taxonomic opinion on the palm family has changed. The basionym is Corypha repens W. Bartram; synonyms include Chamaerops serrulata Michx., Corypha obliqua W. Bartram, Sabal serrulata (Michx.) Schult. & J. H. Schult., and Serenoa serrulata (Michx.) Hook. f.

Description: Shrub; trunk short, usually underground or prostrate, sometimes ascending, often clustered, usually covered with persistent leaf bases. Leaves large, palmately compound, fan-shaped; petioles to 1 m long, rigid, with sharp recurved teeth; leaf without midrib; leaf segments to 20 or more, narrowly lanceolate, pleated, fused at bases, with acute or bifid apices, green or glaucous blue-gray; hastula (triangular extension of petiole at base of leaf segments) obtuse, well developed on upper surface. Inflorescences paniculate, many-flowered, borne between leaves. Flowers creamy white, ca. 6 mm long; calyx cup-shaped, 3-lobed; petals 3, elliptical, reflexed; stamens in 2 whorls of 3 with filaments basally fused to each other and to petals; carpels 3, separated at bases, fused above, only 1 maturing. Fruit a drupe, ellipsoidal or oblong, 1.5–2.5(–3.0) cm long, (1.0–)1.2–1.5(–1.9) cm in diameter; immature fruit yellowish, turning black.

Parts in Commerce: Fruit, often sold partly dried

Identification:

• Ellipsoidal to oblong or ovoid; not globose nor pear-shaped
• 1.5–2.5(–3) cm long, usually 1–1.5 cm in diameter, distinctly longer than wide
• Outer surface black, conspicuously wrinkled when dried
• Base with small circular scar
• When fresh, with layer of pulp over a thin hard endocarp; when dried, pulp shrivels to a thin dry layer clinging to endocarp
• When dry fruit fractured, three thin layers visible: black exocarp, orange to reddish brown mesocarp of uneven thickness, yellowish to reddish brown endocarp
• Inside surface of pit smooth, contains single seed
• Seed broadly elliptical, slightly flattened, usually 10–12 mm long, reddish brown, hard; one side of seed usually with a prominent double groove and ridge, other side smooth except for a small round scar or dimple marking attachment of funiculus
• Odor aromatic, fruity
• Taste aromatic, slightly sweet and acrid

Adulterants: Other palms, especially Sabal etonia Swingle ex Nash and Sabal miamiensis Zona, could potentially be confused with S. repens in the field. The fruits of Sabal species found in Florida are almost spherical, rather than being distinctly longer than wide as in Serenoa. Fresh fruits of S. repens have a definite pulpy mesocarp, whereas drupes of some other species have scanty pulp and a papery exocarp.

References:

British Herbal Medicine Association. British Herbal Pharmacopoeia. BHMA; 1996:166–167.

Hawkes AD. Notes on the palms. 2. Saw Palmetto Serenoa repens Small. Natl Hort Mag. 1950;29:93–95.

Nelson G. The Shrubs and Woody Vines of Florida. Sarasota, FL: Pineapple Press, Inc.; 1996.

World Health Organization. WHO Monographs on Selected Medicinal Plants. Vol. 2. Geneva: World Health Organization; 1999–2002:285–299.

Youngken HW. Text-Book of Pharmacognosy, 5^th ed. Philadelphia, PA: The Blakiston Company; 1943:157–159.

Zona S. The genera of Palmae (Arecaceae) in the southeastern United States. Harvard Pap Bot. 1997;11:71–107.

Zona SA. Arecaceae. In: Flora of North America Editorial Committee, eds. Flora of North America, vol. 22. 2000;95–123.

Figure 67: a–b, Serenoa repens fruit and seed.