Discovering Botanical Families: Euphorbiaceae

The Euphorbiaceae family is certainly one of the most atypical in our flora, probably due to the highly variable morphological and anatomical characteristics of the plants that comprise it. While there are currently more than 300 genera and approximately 6,500 species listed, half of the species come from three main genera: Euphorbia, Croton, and Phyllanthus. Sometimes tropical, sometimes succulent, sometimes woody or even arboreal, Euphorbiaceae behave like true botanical chameleons. 

Although mainly tropical, the family is almost cosmopolitan, as it can be found in the most arid desert landscapes as well as in flower-filled meadows. But it is certainly with the popular poinsettia (Euphorbia pulcherrima) that the family’s geographical distribution reaches its peak, colonizing living rooms around the world as the holidays approach!

As mentioned above, while some families share common characteristics that are obvious and easy to identify at first glance (flowers, fruits, or stems), this is not the case for the Euphorbiaceae family. Identifying them requires more time and attention. This family is made up of species that are often very different from one another. They can be woody or herbaceous, creeping, bushy or erect, sometimes even developing spines to resemble cacti! Their flowers are very discreet and their leaves are sometimes non-existent. The first classification of Euphorbiaceae dates back to 1824 (Jussieu fils), and we can assume that the uniqueness of this family caused botanists some headaches.

Let’s discover the Euphorbiaceae family

This family does not share any particular characteristics. At least, none that are immediately apparent. Here are some of the species that make up this family, demonstrating the complex nature of the Euphorbiaceae.

Leaves: long live diversity!

The leaves are generally petiolate and alternate, opposite or whorled, but sometimes reduced to spines. Although they are most often simple with entire margins, they can also be compound, lobed, or entire with pinnate or palmate veins. To complicate matters further, in some cases the leaves are reduced to scales (Euphorbia myrsinites). There are stipules that are either deciduous or persistent, or even modified into glands. This does not lead us to a precise identification. So let’s continue.

Flowers: a possible distinguishing feature of this family

Euphorbiaceae do not have large, eye-catching flowers. Their unusual but complex inflorescences are extremely small and take the form of cyathia (cyathium), which are small floral structures surrounded by large, fused bracts that attract pollinators. The flowers are unisexual, meaning that the female and male organs are carried by separate flowers.

Thus, in the poinsettia (Euphorbia pulcherrima), it is not the flowers that are red, white, or pink, but the bracts. The real flowers are the small greenish-yellow structures in the center.

Le fruit: une capsule tricoque

This is a common characteristic that deserves to be highlighted. When you have the chance to observe these structures closely, they are highly characteristic of the family. Their typical fruit—a three-parted capsule that splits into distinct segments—is one of the most recognizable traits of the group.

Latex: the signature of the Euphorbiaceae family

Euphorbiaceae are very often plants that exude a whitish, viscous latex, which is generally quite toxic. If you break a stem or tear a leaf from a plant in this family, you will see this white latex appear, which can sometimes be irritating or even toxic. This latex serves several purposes, including deterring herbivores from feeding on the plant, but it also promotes tissue healing and protects against infection. This is why these plants should always be handled with care, as skin irritation is possible.

The rule here is that all Euphorbiaceae generally produce latex, or at least a toxic sap. However, not all plants that produce latex belong to this family. For example, the well-known dandelion also produces latex, but it belongs to the Asteraceae family.

Euphorbiaceae and pearl tea: an unlikely pairing… but delicious!

Cassava (Manihot esculenta), a member of the Euphorbiaceae family, may seem dangerous at first glance: many plants in this family are naturally toxic. And yet, it is precisely from this root that tapioca is obtained, a delicious dessert that can be enjoyed without fear! Thanks to traditional preparation methods, the toxic compounds are eliminated, making it perfectly safe to eat. Thus, cassava transforms risk into a delicacy, a true little tropical miracle.

Croton: a colorful Euphorbiaceae!

Grown mainly as a houseplant in our latitudes, croton is distinguished by its spectacular foliage, with vibrant colors ranging from green to yellow, orange, red, and sometimes even purple. This vivid palette is due to the pigments present in its leaves and explains its popularity in tropical decor. Like many members of its family, croton produces an irritating white latex, so it is best to wear gloves when pruning or repotting. Despite this, it remains a robust and highly decorative plant, perfect for adding an exotic touch to any space.

Some plants of this family

Houseplants

Crown of thorns (Euphorbia milii)

Three-cornered spurge (Euphorbia trigona)

Pencil tree (Euphorbia tirucalli)

Poinsettia (Euphorbia pulcherrima)

Croton (Codiaeum variegatum)

Devil’s backbone (Euphorbia tithymaloides)

Madagascar spurge (Euphorbia leuconeura)

Annuals

Common castor bean (Ricinus communis)

Zanzibar castor bean (Ricinus communis syn. Ricinus zanzibarensis)

Wood spurge (Euphorbia amygdaloides). Perennial in warmer climates.

St. John’s wort spurge (Euphorbia hypericifolia ‘Inneuphdia’)

Perennials

Polychromatic spurge (Euphorbia polychroma)

Cypress spurge (Euphorbia cyparissias)

Myrtle-leaved spurge (Euphorbia myrsinites)

Wild plants

Sun spurge (Euphorbia helioscopia)

Spotted spurge (Euphorbia maculata)

Food plant

Manioc (Manihot esculenta syn. Manihot utilissima)

Plants for industrial use

Rubber tree (Hevea brasiliensis)

In summary:

• Very diverse family
• Frequent presence of white latex, which is often irritating or toxic.
• Discreet flowers (cyathia), but bracts often colorful and very visible.
• Three-seeded fruits

How can we sum up such a vast and diverse family in just a few words? How can we broadly define a family whose attributes are so variable? The botanists who came before us managed to do so, but we can well imagine the Herculean task they faced in taming this beast. The uniqueness of the Euphorbiaceae family probably made them an object of desire for them, and fortunately for us today! We can only admire the diversity of Euphorbiaceae and draw inspiration from it. So, at this time of year when we celebrate one of the most famous Euphorbiaceae, the poinsettia, let’s give a nod to botany: may the diversity and creativity of Euphorbiaceae inspire your decorations, your projects… and your celebrations. On that note, happy holidays!

In our next installment… Bromeliads!