Sabal causiarum

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Sabal (SAH-bahl)
causiarum (kawz-ee-AHR-uhm)
Sabal causiarum infructescence.JPG
Bronx Co. Conservatory of the New York Botanical Garden, NY. Photo by Dr. Christine D. Bacon.
Scientific Classification
Genus: Sabal (SAH-bahl)
causiarum (kawz-ee-AHR-uhm)
Sabal haitensis (1931), Sabal questeliana (1944)
Native Continent
Habit: Solitary
Leaf type: Costaalmate, with a recurving leaf.
Survivability index
Common names
Puerto Rican hat palm, Puerto Rico Palmetto

Habitat and Distribution

Sabal causiarum has a natural range that includes Puerto Rico, the island of
Sabal causiarum, Bob Hasting's garden, Spring Valley, CA. Ron McCullough standing in for scale. The large papery liguels are the key to id-ing this species.
Hispaniola (Dominican Republic and Haiti); southwestern Haiti and eastern Dominican Republic, Anegada and Guana Island in the British Virgin Islands, and adjacent Caribbean islands of the Greater Antilles.between sea level and 100 metres (328 ft) above sea level.


Stems: Solitary, massive, upright stems to 15 m tall and to 70 cm diameter. Leaf bases usually fall away quickly to leave a smooth gray stem with close rings. Leaves: Costapalmate, induplicate, twisted into several planes with a strongly arching costa, to 2 m wide. Leaf segments rigid, with numerous fibers along the segment margins. Petiole bases split. Flowers and fruits: Inflorescences exceeding the leaves in length, arching or pendulous, and branched to three orders. Flowers creamy white, bisexual. Ripe fruit black, spherical, 7-11 mm diameter. ( Editing by edric.

Sabal causiarum is a fan palm with solitary, very stout stems, which grows up to 10 metres (33 ft) tall and 35–70 centimetres (14–28 in) in diameter. Plants have 20–30 leaves, each with 60–120 leaflets. The inflorescences, which are branched, arching or pendulous, and longer than the leaves, bear globose, black fruit. The fruit are 0.7–1.1 centimetres (0.3–0.4 in) in diameter; fruit size and shape are the main characteristics by which this species differs from Sabal domingensis. Editing by edric.


Adaptable to different soil types but prefers very well drained soils. The only pest problems for this palm are leafhoppers and the ganoderma fungus. Light: Needs bright sunlight. Moisture: Tolerates dry conditions once established. Mature height: 50' Mature spread: 16'. Cold Hardiness Zone: 8b

Comments and Curiosities

This is a tillering palm, it exhibits saxophone style root growth (it has a heel), keep top third of heel above soil elevation!

Uses: As is reflected in both the common and scientific names of the species, the leaves of Sabal causiarum are used in the manufacture of hats. In 1901 Orator F. Cook described a hat-making industry centered in the village of Joyuda in Cabo Rojo, which made "large quantities" of hats from the leaves of this species. According to Andrew Henderson, this industry had declined considerably by the late 1900's. Leaves of the species are also used to make baskets, mats and hammocks, and older leaves for thatch. It is also planted as an ornamental or street tree due to its "massive, stately appearance."

Etymology: It is S. causiara as opposed to S. causiarum, by the way, according to the international laws of nomenclature where the feminine ending is required for the specific name if present in the generic name (as in S. bermudana, S. mexicana, S. uresana, S. etonia etc.). (Rare Palm

Diagnostic features: Solitary, massive, upright, smooth gray stems with close leaf scar rings, costapalmate leaves twisted into several planes, petioles with light brown ligules and inflorescences longer than the leaves. Andrew Henderson and colleagues noted that Sabal maritima, S. causiarum and S. domingensis form a species complex that may constitute a single species.

The species are readily distinguished on the basis of fruit size and shape. Sabal domingensis has pyriform fruit, 11.5-14.1 (12.7 ± 0.7) mm in diameter and 11.0-14.4 (13.1 ± 1.0) mm high. Sabal causiarum has spherical or occasionally oblate-pyriform fruit, 7.1-10.8 (9.8 ± 0.5) mm in diameter and 7.5-10.4 (9.4 ± 0.7). Sabal maritima has oblate-pyriform to oblate-spherical fruit, 8.5-14.2 mm in diameter, 8.4 - 1 2.6 mm high. A similar size difference is found in the seeds: 8.0-10.4 mm in diameter, 5.1-7.1 mm high for S. domingensis versus 5.9-7.8 mm in diameter, 4.3-5.7 mm high for S. causiarum and 6.5-9.7mm in diameter, 4.5-6.2mm high, with a smooth (rarely some-what beaked) funicular remnant.

Another difference is that the petioles of S. maritima are densely covered with light-colored scales and appearing whitish or tan with a small, triangular to square-shape ligule at petiole base. S. maritima also has a rachillae with very crowded flowers, whereas the flowers are not crowded much in S. causiarum. Donald Hodel also mentions that Sabal causiarum can be distinguished from S. domingensis and S. causiarum by the presence of conspicuous, large, tan, flap-like ligules at petiole base. This characteristic is not mentioned in Scott Zona’s 1990 monograph of Sabal.

This palm is distinguished from other Sabals by its massive smooth gray trunk which can grow up to 4 ft (1.2 m) in diameter! Most Sabals retain their old leaf bases on the trunk, creating a textured crisscross or "cabbage leaf" pattern instead of a smooth trunk. The leaves of Puerto Rican hat palm are large, usually about 6 ft (1.8 m) long and just as wide. They are costapalmate, which means the petiole, or leaf stem, extends into the leaf. The leaves are deep green in color and are deeply divided to about half their length into several segments which may droop at the ends. The Puerto Rican hat palm forms a dense canopy of about 40 leaves. As the older leaves droop to 45-90 degree angles from the trunk, they turn brown, die and fall off. Many other Sabal species, like Florida's native cabbage palm (Sabal palmetto) tend to retain a 'hula skirt' of dead leaves about its trunk. (

"Sabal causiarum is one of the biggest sabals with the largest fans. Sabal causiarum happens to also be one of the hardiest of the bunch, and will not sustain any leaf damage even with temperatures in the low 20's. Out of all the Sabals, causiarum has proven itself in the cooler West coast climate as it grows successfully even in Seattle. If you have to pick only one sabal to grow in Northern California, causiarum is probably your safest bet." (Dr. Axel kratel)

This sabal also happens to be one of the faster growing sabals in Southern California, making it a good choice for Northern California. Unfortunately, sabals are not widely planted in California as a whole, so it's hard to find specimens in Northern California. Dick Douglas had a large trunking specimen in Walnut Creek.

External Links


Phonetic spelling of Latin names by edric.

Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.

Special thanks to, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.

Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).

Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.

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