Late February 2021

Introduction

The walkway along the ocean into Old San Juan was rebuilt a few years ago. The Paseo de Puerta de Tierra, as it is called, includes signage. One can read about the historical sites along the path – the first, second and third lines of defense, the powder magazine in Parc Luis Munoz Rivera, the ruins of a Spanish observation post.

Some of the signs identify vegetation. I find those informative but intimidating. I realize how little I know about tropical vegetation. So I decided to learn something about palm trees. It is at least a start.

There are palm trees everywhere here. Of course, one would expect that, given the tropical environment. Street vendors sell fresh coconuts. They use machetes to lop off the top to get at the liquid inside. The coconut water is a local treat.

I looked to buy a field guide to help identify palm trees. I couldn’t find one. So I went online. There are resources but I found them difficult to use. For one thing, you need a specialized vocabulary. The leaves (technically fronds) can be pinnate or palmate, or maybe entire or bipinnate. And then there are the trunks. And the roots.

Palm Trees: Background

Palm trees evolved about 80 million years ago, during the late Cretaceous. Some survived the mass extinction that marked the end of the Cretaceous era, an abrupt event marked by the K-Pg boundary. Since then, the Arecaceae have evolved into about 181 genera and 1200 species with most found in tropical and sub-tropical climates.

Palms (known more technically as the Arecaceae) are perennial, woody, flowering plants. They usually have a prominent trunk. The Arecaceae are, like the grasses, monocotyledons – that is, a seed produces one shoot with one leaf. They can take the form of trees, climbers, shrubs, or be stemless.

Palm trees, like other monocotyledons, do not exhibit the secondary growth common to woody plants. The wood does not have growth rings. So-called anomalous secondary growth does occur, but to a lesser extent that woody plants. This gives palm trees their slender appearance.

Palm Trees: Structure

Identification of palms starts with the features noted above. One looks at the fronds first, then the details of the trunk. That usually provides a pretty good start.

Most palm trees exhibit either pinnate or palmate leaf structure.

Palm trees are widely used in ornamental plantings. I suspect landscapers planted almost all the palm trees I see in San Juan. That means some are native species, some are not. That makes their identification that much more challenging.

Specific Palm Trees

Here are some of the palms I’ve identified. I confess I’ve made liberal use of the signage along the Paseo de Puerta de Tierra. But I did also use other sources. Please refer to Notes and Sources.

Puerto Rican Hat Palm – Palma de Sombrero (Sabal causiarum)

This palm tree is native to Puerto Rico and Hispaniola. It is characterized by a thick, straight trunk with a small crown of palmate fronds. In fact, the crown often seems too small given the tree’s height, often over 35 feet.

The fronds were used to manufacture hats, an industry centered in Joyuda, in the southwest part of the island. The industry went into decline in the early twentieth century.

Puerto Rico Royal Palm – Palma Real (Roystonea borinquena)

Another Puerto Rico native, this palm is closely related to royal palm trees in Cuba, Hispaniola, Honduras, Guyana, and Florida, among other West Indies locations. These are tall, stately palms with a graceful crown of feathery fronds and often used in ornamental plantings. Note the prominent crownshaft.

Spindle Palm – Palma Botella (Hyophorbe verschaffeltii)

These slow-growing palms are native to the Mascarene Islands where they are in danger of becoming extinct. They exhibit a smooth trunk that can bulge in the middle, and a distinct crownshaft. The fronds are pinnate. The inflorescences are prominent and covered in a spathe. Spindle palms are often grown in large containers.

Fiji Palm – Palma de abanica (Pritchardia pacifica)

Pritchardia is a genus of 37 species, with most found on the Hawaiian Islands. They are solitary fan palms with full, dense crowns of large, stiff palmate fronds. They do well when planted in groups, and grow up to 35 feet high.

The Fiji palm is found, as its name implies, on the Fiji Islands. Some experts think it originated on Tonga before being introduced to the Fijis. It is said the fronds were used as fans for the Fijian royalty.

Manilla Palm – Adonidia (Veitchia merrillii)

The genus Veitcha includes eighteen species, all located in the Western Pacific – the Phillipines, New Hebrides, and Fiji. They exhibit feathery pinnate fronds and a prominent crownshaft.

The Manilla Palm is native to the Philippines. It produces clusters of bright red fruit around Christmas time; the tree is sometimes known at the Christmas palm. It can grow to a height of 25 feet.

The fruit of the Christmas palm is edible, though said to be not pleasant. I wonder if it could be made into a jam or jelly, or maybe a chutney.

Mexican Fan Palm – Palma Washingtonia (Washingtonia robusta)

The genus Washingtonia includes two species, both native to the United States west coast, and Baja and Sonora, Mexico.

Mexican fan palms are widely cultivated. Examples can be found in Texas, Florida, Hawaii, the Canary Islands, Spain, Italy, Israel, and Lebanon.

The Mexican fan palm grows as tall as 80 feet, on a thin, smooth trunk. It displays a compact crown of palmate fronds. They are often planted in rows along avenues, as they are in the image above.

Foxtail palm – Palma cola de zorra (Wodyetia bifurcata)

The genus Wodyetia contains only one species. The foxtail palm is native to northeastern Australia. It has become a popular ornamental plant, so much so the native trees are in danger from seed poachers.

This species exhibits a slender, closely ringed trunk with graceful pinnate fronds. It has a slender crownshaft and produces large, orange-red fruit. It can grow to 35 feet in height.

Date Palm – Palm datilera (Phoenix dactylifera)

The Phoenix genus consists of about seventeen species and are found pretty much around the world. The date palm (P. dactylifera) shows greyish-green pinnate fronds in a graceful crown. These trees lack a crownshaft. Trees are either male or female; both are needed for fertilization. They can grow up to 70 feet high.

The date palm is famous for its fruit, which has been known since antiquity. However, these trees bear fruit only in hot, dry climates. The north coast of Puerto Rico is too wet and humid for these plants to bear fruit. I wonder if that is true in the generally drier, warmer southern regions of the island. Perhaps Puerto Rico can become a date-exporting nation. In any case, the date palm is widely used in ornamental plantings.

Coconut palm – Palma de coco (Cocos nucifera)

Cocos is a one species genus. Coconut palms have large spreading crowns of pinnate fronds. The smooth, slender trunks are often curved, a rare trait among the palms. Given their wide distribution, their origin is uncertain. Most experts think they originated in the Western Pacific.

A coconut tree typically produces 30 or so fruit a year. The fruits are technically drupes and not nuts. (I’m glad the fruit is misnamed – I’m not sure I could handle writing about cocodrupes). They have a hard shell and weigh four or five pounds. The trees can grow to 80 feet; one has to think a falling coconut represents some danger. In 1982, Dr. Peter Barss, a doctor practicing in Papua, New Guinea, published a paper with the ominous title “Injuries Due to Falling Coconuts” in the Journal of Trauma. Barss noted that, in his practice, 2.5% of the trauma admissions were the result of falling coconuts. He did not observe any deaths.

Barss’ work became the fuel for a persistent urban legend. People claimed more people died from falling coconuts than shark attacks. Officials in one town in Queensland, Australia removed coconut palms from the town beach. Poets got into the fray. The American poet Frederick Seidel wrote a poem he titled “Coconut.” It contains the following lines:

A coconut can fall and hit you on the head,

And if it falls from high enough can kind of knock you dead

Dead beneath the coconut palms, that’s the life for me!

(See the Wikipedia article Death by coconut for a complete attribution).

Now, there have been deaths by falling coconuts. Here are a few.

• Sometime around 1777, a concubine died after she was struck by “a falling green nut.” She was with the court of King Tetui of Managia in the Cook Islands.
• Four people died from falling coconuts in Sri Lanka in 1883.
• A US marine died when a falling coconut hit him in the head as he slept. This was on Guadalcanal, in 1943.
• In 1991, in Sri Lanka, a mourner at a funeral died when struck by a coconut.

The case of the US marine is intriguing. Imagine him, having survived an amphibious assault, battles with Japanese infantry, air attacks, and bombardment by Japanese battleships, dead from a falling coconut.

So some people have died from falling coconuts. I don’t know how that number compares to deaths by shark. I do know that, when I go to the the beach, I find a place in the shade of a coconut tree. But I look up to make sure I’m not directly under any hanging nut, or drupe, or whatever.

Three Not Yet Identified

Unknown One

I used the signage along the Paseo de Puerta de Tierra to identify the palm trees described above. I checked the identification with my palm tree book. See Notes and Sources. But there are several I cannot identify. Here are three of the most prominent.

Unknown number One (above) shows multiple trunks and large palmate fronds. I think it is a palm – I suppose it could be a Cycad or a Cyclanth or a Pandans or possibly a Cordylines. These plants are closely related to palms and are often confused with them by the inexperienced observer, of which I am a perfect example.

Unknown Two

I first thought Unknown 2 (above) was a member of the genus Phoenix and was thus a member of the date palms. It does share the unusual trunk structure and lack of a distinct crownshaft. However, the fronds are palmate, not pinnate.

The more mature example of Unknown 2 shows the palmate fronds to better effect.

Unknown Three

The third unknown has one very large palmate frond arranged in one plane. I’ve seen it used in ornamental plantings – for example, in the thin grass strip between a sidewalk and a building. One can see a good example of this type of planting on the south side of the old federal courthouse in Old San Juan.

Final Thoughts

I guess I’ve learned a bit about palm trees. It is amazing what one can see when one opens their eyes to what’s around them.

Notes and Sources

I relied heavily on the book Palms Throughout the World, by David L. Jones, Smithsonian Institute Press, Washington, D. C., 1995. The two figures are from this book. I got my copy via Amazon.

I used several articles in Wikipedia. The main article – Palm Trees – has links to articles about specific palm trees and other useful links.

I relied on the Wikipedia article Death by Coconut for information on that morbid topic.

The photos are all mine, edited with Adobe Lightroom and/or Photoshop.