What are the largest plant families?

Grass is the most successful plant

What are the most numerous plant families that exist? We live on a planet with a great diversity of plant life, where we can contemplate the beauty of a large tree, but also of the tiny flowers that produce many herbs that barely exceed eight inches in height.

The climate, the land, the location, … all these are factors that shape the evolution of each of the plants, because what every living being wants is precisely to continue existing. Thanks to that, the survival instinct makes the plant kingdom what it is today: a spectacle in itselfone that humans have the opportunity to enjoy.

What are botanical families?

Before going into the subject, I would first like to explain what a family is in botany, since in this way if you are curious to know which are the most numerous plant families, you will know exactly how important they are. Well, in the world there are about 400.000 accepted plant speciesnot counting the varieties and not even the cultivars (if so, that number would surely be close to one million … or it may even exceed it).

As humans that we are, one of our characteristics is that we like to classify things, since it is much easier for us to learn about them. Therefore, the experts, in this case the botanists, what they do is group plants that are as similar as possible, not only in appearance, but also in terms of their evolution and therefore also their genetics.

Taking all this into account, today we know, for example, that although Cycas and palms they look quite alike, they don’t really have any relationship. While the former are considered living fossils since they began to evolve more than 300 million years ago, palm trees are more ‘modern’ plants since their evolution began about 140 million years ago.

But that’s not all: Cycas are gymnosperm plants, that is, they are plants that do not protect their seeds in a fruit (be it capsule, legume, or etc.), but rather those reddish balls that we see are the seeds; palms, on the other hand, are angiosperms, that is, they protect them in a fruit that is usually fleshy, such as dates.

As you can see, identifying plants is much more than looking at their appearance. For all this, today more than 100 botanical families have been established.

What are the most numerous plant families that exist?

Now that we know that it is a botanical family, we have to talk about the most numerous. There are many that are very big, but without a doubt the ones that deserve to be in the top 5 are the following:

Asteraceae (compound plants)

View of the Aster tataricusView of the Aster tataricus

Image – Flickr / jacinta lluch valero // aster tataricus

It is the most numerous by far. In her about 32.913 species are gathered, divided into about 1911 genera. These are normally herbaceous plants, although they can be trees, shrubs or climbers. They can be annual, biennial or perennial. The leaves are alternate and spiral generally greenish.

The flowers are small, hermaphroditic or rarely unisexual or sterile, and are grouped in inflorescences composed of chapters. The fruits are cyselas, that is, the seed is attached to numerous very light hairs that will help it to move away from the mother plant.

In this botanical family we find the Aster, Senecio, or the Helichrysum, among others.

Orchidaceae (orchids)

View of Phalaenopsis orchidView of Phalaenopsis orchid

Image – Wikimedia / sunoochi from Sapporo, Hokkaido, Japan // Phalaenopsis hygrochila

Orchids are in second place, something that lovers of these plants may like. It is estimated that there are about 25.000 species (some say there are about 30.000) divided into 800 genera. They are herbaceous, perennial or annual plants, with a terrestrial or epiphytic habit, or sometimes climbing plants. In the case of terrestrial ones, the stems are rhizomes or corms, whereas in epiphytes the leaves thicken at the base, forming pseudobulbs.

The leaves are simple, often alternate, spiral, distal or whorled, with or without petioles. The flowers are among the most complex in the plant kingdom, even in certain species of orchids take animal forms, very bright colors. The fruits are berries that contain the seeds.

Examples of this family we have at Phalaenopsis, Cattleya, or Dendrobium, among others.

Fabaceae (legumes)

View of the Caesalpinia pulcherrimaThe most beautiful view of the Caesalpinia

Image – Wikimedia Commons / Felix Vieira

This is a family that also has great economic importance, not only because many produce edible seeds, but there are also many with great ornamental value. In her we found 19.400 species divided into about 730 genera of herbs (annual, biennial or perennial), trees, shrubs and vines. The leaves are generally alternate, evergreen or deciduous, pinnate or bipinnate, green in color.

Its flowers can be small or large, composed of five brightly colored petals, and are grouped in cluster-like inflorescences. The fruits are more or less long legumes that contain seeds that are often blackish and leathery.

Examples of legumes we have, for example, Delonix direction (flamboyant), The Acacia, Caesalpinia or vicia sativa (peas).

Poaceae (grasses)

View of the bambooView of the bamboo

Image – Wikimedia Commons / Wikimedia Commons / Phyllostachys viridiglaucescens

They are the fourth largest family, with 12.100 described species spread over more than 820 genera. Despite being the fourth, it is the first in terms of economic importance, since we feed a large part of them … and many farm and poultry animals, as well as some domestic ones.

In general we talk about grasses, woody, tussock, rhizomatous or stoloniferouswhich can be annual, biennial or perennial depending on the species. The stems are cylindrical to elliptical, with hollow or solid internodes (like corn), and from them sprout long, alternate green leaves. The flowers are grouped in spikelet-shaped inflorescences, and are unisexual or hermaphroditic. The fruits are small and dry.

Examples of grasses we have the Triticum (wheat), The Oryza sativa u The most beautiful rice (rice), The zea mays (corn), The common barley (barley), the subfamily Bambusoideae (bamboo) nor Oats.


View of the Gardenia jasminoidesView of the Gardenia jasminoides

Image – Wikimedia / Alpsdake // Gardenia jasminoides

And last but not least, we are going to talk to you about the Rubiaceae. This family comprises more than 10.000 species divided into about 600 generaand they are trees, shrubs, herbs, or climbers, generally of terrestrial habit although there are some that are epiphytes. The leaves are opposite, whorled or rarely pinnatifid, perennial or sometimes deciduous.

The flowers are grouped in terminal inflorescences, and are actinomorphic or rarely zygomorphic. The fruits are simple or multiple, and can be drupes or capsules, and contain the seeds.

Examples of plants belonging to this family are: Gardenia, Gallium, or the bouvardia.

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What are the largest plant families?

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