Two or three leaf-color morphs are found in Serenoa (A. D. Hawkes 1950). The green type is more widespread, and the glaucous or blue-gray type seems to be more abundant in coastal sites of southeastern Florida. Serenoa repens forma glauca Moldenke was described as differing from the typical form of the species in having glaucous leaf blades (H. N. Moldenke 1967). Since a type specimen for S. repens is lacking, it is impossible to know if Moldenke’s form differs from the type. The genetic basis for these color differences is not understood.
Serenoa repens apparently is pollinated by bees. Flowering and fruiting are not necessarily annual events, and some years see more abundant flowering than others (J. B. Hilmon 1968). Even when flowering is abundant, fruit production is erratic (D. Smith 1972); the causes are quite unknown. When fruits are present, they are eagerly sought by black bears (D. S. Maehr 1984; D. S. Maehr and J. R. Brady 1984), white-tailed deer (R. F. Harlow 1961), raccoons, foxes, opossums, and various birds (J. B. Hilmon 1968).
Serenoa fruits are the source of a steroidal drug that inhibits the conversion of testosterone to dihydrotestosterone, which binds to receptors in the prostate gland and in hair follicles (B. C. Bennett and J. R. Hicklin, in press1998). This inhibition is the biochemical basis for the use of Serenoa extracts in treating benign prostrate swelling and baldness. Bennett and Hicklin provided a complete review of the uses of Serenoa in traditional and modern medicine, as well as its use as a fiber and thatch plant.
This plant is noted for its ability to effectively treat benign prostatic hyperplasia and many other medical uses. Additionaly, Serenoa repens' petiole fibers are used by the Seminoles of southern Florida to make dolls.
Serenoa repens may be confused in the field with some low-growing species of Sabal palms, but Serenoa repens petioles (leafstalks) are covered with many tiny prickles and the leaves lack the prominent extension of the petiole along some or much of the length of the leaf that is evident in Sabal. Everglade Palm (Acoelorrhaphe wrightii) has green flowers (rather than white) and larger, stouter, usually curved orange prickles on the petiole. (Petrides 1988)
Serenoa repens, commonly known as saw palmetto, is a small palm, growing to a maximum height around 7–10 ft (2.1–3.0 m).
It is the sole species in the genus Serenoa. The generic name honors American botanist Sereno Watson.
It is endemic to the subtropical and tropical Southeastern United States,[4] most commonly along the south Atlantic and Gulf Coastal plains and sand hills. It grows in clumps or dense thickets in sandy coastal areas, and as undergrowth in pine woods or hardwood hammocks.[5]
Erect stems or trunks are rarely produced, but are found in some populations. It is a hardy plant; extremely slow-growing, and long-lived, with some plants (especially in Florida) possibly being as old as 500–700 years.[6]
Saw palmetto is a fan palm, with the leaves that have a bare petiole terminating in a rounded fan of about 20 leaflets. The petiole is armed with fine, sharp teeth or spines that give the species its common name. The teeth or spines are easily capable of breaking the skin, and protection should be worn when working around a saw palmetto. The leaves are light green inland, and silvery-white in coastal regions. The leaves are 1–2 m in length, the leaflets 50–100 cm long. They are similar to the leaves of the palmettos of genus Sabal. The flowers are yellowish-white, about 5 mm across, produced in dense compound panicles up to 60 cm long.
Among live oak and sabal palmetto in habitat, Punta Gorda, Florida
In Manatee Springs State Park, Florida
Winding trunks of an old clump, Manasota Key, Florida
A very old example of the silver variant, Largo, Florida
The fruit is a large reddish-black drupe and is an important food source for wildlife and historically for humans. The plant is used as a food plant by the larvae of some Lepidoptera species such as Batrachedra decoctor, which feeds exclusively on the plant.
Saw palmetto extract has been studied as a possible treatment for people with prostate cancer and for men with lower urinary tract symptoms associated with benign prostatic hyperplasia (BPH).[5][7][8] As of 2018, there is insufficient scientific evidence that saw palmetto extract is effective for treating cancer or BPH and its symptoms.[7][8][9]
One 2016 review of clinical studies with a standardized extract of saw palmetto (called Permixon) found that the extract was safe and may be effective for relieving BPH-induced urinary symptoms compared against a placebo.[10]
Indigenous names are reported to include: tala or talimushi ("palmetto's uncle") in Choctaw; cani (Timucua); ta ́:la (Koasati); taalachoba ("big palm", Alabama); ta:laɬ a ́ kko ("big palm", Creek); talco ́:bˆı ("big palm", Mikasuki); and guana (Taíno, possibly).[11] Saw palmetto fibers have been found among materials from indigenous people as far north as Wisconsin and New York, strongly suggesting this material was widely traded prior to European contact.[12] The leaves are used for thatching by several indigenous groups, so commonly that a location in Alachua County, Florida, is named Kanapaha ("palm house").[13] The fruit may have been used to treat an unclear form of fish poisoning by the Seminoles and Lucayans.[14]
Serenoa repens, commonly known as saw palmetto, is a small palm, growing to a maximum height around 7–10 ft (2.1–3.0 m).