Chamaerops is a genus of flowering plants in the palm family Arecaceae. The only currently fully accepted species is Chamaerops humilis, variously called European fan palm, or the Mediterranean dwarf palm. It is one of the more cold-hardy palms used in landscaping in temperate climates.
Apart from the fully accepted Chamaerops humilis there currently are a few species of unresolved status plus tens of species synonymised with Chamaerops humilis. The species Chamaerops humilis itself has three accepted varieties as follows:
There also are at least two cultivars.
The genus Chamaerops is closely related to the genus Trachycarpus. The genera differ in that Trachycarpus lacks the clumping habit only forms single stems without basal suckers), the spiny leaf stems (spineless in Trachycarpus), and in small details of the flower anatomy.
Chamaerops humilis is a shrub-like clumping palm, with several stems growing from a single base. It has an underground rhizome which produces shoots with palmate, sclerophyllousleaves.
The stems grow slowly and often tightly together, eventually reaching 2–5 m tall with a trunk diameter of 20–25 cm. It is a fan palm (Arecaceae tribe Corypheae), and as such, has leaveswith petioles terminating in rounded fans of 10–20 leaflets. Each leaf is up to 1.5 m long, with leaflets 50–80 cm long. The petioles are armed with numerous sharp, needle-like spines; these may protect the stem growing point from browsing animals.
The flowers are borne in dense, short inflorescences at the tops of the stems. The plants usually, but not invariably, are dioecious with male and female flowers on separate plants. The prophyll covers the flowers on the inflorescence until the sexual phase (anthesis) and then splits open apically into two triangular lobes. The number of flowers per inflorescence is highly variable for both male and female plants, depending on the size of the inflorescence. Female flowers are tri-ovulate. Unripe fruits are bright green, turning to dull yellow to brown as they ripen during autumn (September–November). The seed (usually 0.6–0.8 g) contains a small cylindrical embryo, which is surrounded by several layers, from inner to outer as follows:
Chamaerops humilis has a wide distribution in uncultivated land, and it is adapted to regimes of frequent burning, which it survives largely by re-sprouting from underground rhizomes and from fire-damaged stems. Such factors make the species ecologically important in preventing erosion and desertification and in providing shelter and food to many species of animals.
Apart from its material benefits, this palmetto is of emotional value as a charismatic component of the "garrigues" and "macchias" of the Mediterranean coastline.
The leaves of the adult plants have been used to make brooms and for weaving mats, carrier baskets, and similar articles. For finer work the young, unopened leaves are treated with sulphur to soften them softer and provide supple fibre.
The husk, known in southern Spain as "higa", is edible before it becomes too tough to eat as it matures. Because of their bitterness and high tannin content, the fruit are not used for human food, but in traditional medicine they have been used as an astringent.
Urbanization and other human activities are making such rapid inroads into the natural habitat of palmetto that they are raising concerns about its future and that of its environment. Accordingly there is an increase in regulations to protect both its stands and those of associated Mediterranean endemics.
Another conservation problem is that particularly in the northernmost parts of its natural range, Chamaerops humilis is seriously threatened by an introduced South American moth Paysandisia archon.