There is a firm belief that palm trees are trees. It is a phrase that is written in books, blogs and encyclopedias. But the reality is that They are two very different types of plants., too. It's not like comparing a pine to a maple: the former is a conifer, and the latter is a broadleaf tree, yes, but they have a common ancestor and a similar way of life, so they are both trees. Palm trees are another story.
But what is the difference between them? What do we have to look at to see if a plant is a tree or a palm tree? Next I am going to explain to you why palm trees are not trees.
They are monocotyledonous plants
Image – Wikimedia/RickP
Like grasses, although palm trees are really megaforbias (giant grasses). When the seeds germinate, a single cotyledon (primitive leaf) sprouts, which is very reminiscent of lawn grass for example. This leaflet can be divided into two leaflets, as is the case with the Wodyeta for example, but it is usually simple, like that of the Phoenix or Washingtonia.
Now, being a monocotyledonous plant is more than that, as you will be able to see now.
They only multiply by seeds
The cutting method is widely used in the propagation of trees, but in palm trees it is difficult to get it right. On the one hand, there are very few that develop several trunks, such as the Chamaerops humilis, Phoenix dactylifera, Cyrtostachys renda o Nannorhops ritchiana; and on the other, these plants do not have a cambium or secondary meristem. And without this meristem, which is made up of meristematic cells, there can be no growth.
In fact, its structure is fibrous, and not woody. For this reason, its trunk is not a true trunk, since they also do not develop growth rings, but this is known by the name of stipe. If we want to reproduce a palm tree asexually, we will have to separate the suckers -in case it develops them- with roots.
They grow in height, not in diameter
Image - Wikimedia / Forest & Kim Starr
Palm trees, like other herbs, can only grow tall. This they do this thanks to a terminal meristem that is protected in the terminal bud. Therefore, what we could confuse with the bark of the stipe are leaf remains that have been drying.
And not only that, when, for example, they are kept in small pots for a long time and after a few years they are planted in the ground, as they grow, it will be seen that the stem or false trunk has a marked narrowing at a certain height.
Palm trees are not deciduous
Of the more than 3 thousand species of palm trees that have been described, there is not a single one that loses its leaves (at least, not as a result of the weather). Like all plants, they do lose them as those leaves age and dry, but nothing more. Our protagonists always need to have a minimum number of leaves throughout the year to grow and carry out photosynthesis.
Even in the event of a fire or a major pest attack, and as long as the apex (or growth guide) has not been damaged, new ones will soon sprout.
The leaves are of three types
Tree leaves can be many types: lanceolate, obovate, elliptical, paripinnate, bipinnate,... But those of palm trees only have three: pinnate, costapalmate and palmate.
- pinnate leaves: they are formed by pinnae or leaflets that sprout perpendicularly on the rachis, which is the stem that joins it to the false trunk. Examples: Phoenix, Roystonea, Cyrtostachys, Butia, Syagrus.
- palmate leaves: they are the ones that are fan-shaped, like those of the Washingtonia.
- Costapalmate leaves: they are round or oval in shape, divided into numerous segments that tend to "hang", as is the case with Sabal species.
The flowers of the palm trees are grouped in inflorescences always
We have all seen flowering trees at some point: many of them are showy, with their parts well differentiated. But those of palm trees are different: they always appear grouped in inflorescences, and sometimes these branch. The little flowers are very small, one centimeter in diameter or less, and are usually light in color (yellow, cream; rarely pink or red).
Not only that: there are certain species that only flower once in their life, such as the Hyphaene thebaica or the Tahini spectabilis. These are monocarpic plants. And no, there is no tree that is.
Its roots are adventitious
Adventitious roots are those that sprout from the same point, and all have more or less the same length.. In the case of those with palm trees, they start out like this, but then there are others that can be aerial. For example, they can produce them to improve anchoring to the ground, either because they are in an area where the wind blows strongly, or because they grow near watercourses.
How deep do they go? Depends on the species and where you live, but they can measure up to 15 meters if the ground is soft and the specimen is an adult. But contrary to what it may seem, they do not have the strength to break pavements. This is something that can be verified simply by observing a palm tree that has grown on the asphalt: once it runs out of space, its growth will stop, and if it has free access on one side, it will grow towards that side.
One last fact: palm trees appeared much later than trees
Although it is not a physical difference, it is interesting to know that palm trees are more "modern" plants. In fact, appeared about 140 million years ago; Instead, it is known that the ancestors of the Ginkgo biloba, which is one of the most primitive trees, already existed more than 300 million years ago.
When a “new” type of plant emerges, it is normal for similar new species to start emerging soon after., as they colonize other parts of the territory, and no more than a hundred million years later. Climate and land conditions change, more or less, slower or faster, but they do change. When that happens, plants have to adapt as soon as possible if they want to survive.
And for all this, palm trees cannot be considered trees.