Discovering Botanical Families: Solanaceae

Summer is in full swing and Solanaceae are taking center stage in the vegetable garden. Gardeners are well aware that several members of this family are known for their tasty fruits and more than generous harvests. Just think of the vibrant tomato, the spicy chili pepper, the plump bell pepper, and the sweet eggplant. Solanaceae are not afraid of heat waves and remain unfazed by the sun’s scorching rays, even daring to double their vigor when the muggy July heat so often dictates immobility.

This family of dicotyledonous plants, tightly woven around heat, is particularly prevalent in tropical and temperate regions. South America alone has forty endemic genera, which is significant considering that the family has nearly a hundred. Associated with these hundred genera are some 2,700 species, including herbaceous plants, shrubs, vines, and sometimes even trees.

Plants in the Solanaceae family also produce alkaloids and are therefore generally toxic to varying degrees. History is full of anecdotes recounting the tragic ends of glorious figures who succumbed to the scent of a beverage overly flavored with belladonna or mandrake. But let’s leave that to the historians and move on to the botanical description of the Solanaceae.

Morphological Characteristics

Leaves and Stems

• Often hairy or slimy, with glandular trichomes (hairs) (e.g., tomato, petunia)
• Leaves always alternate
• No stipules
• Leaves often fragrant
• Several genera form tubers (stem or root depending on the genus).

Flowers

• Generally hermaphroditic.
• Usually actinomorphic (radial symmetry)
• Petals and sepals grouped in 5 (pentamerous flowers). Note: some cultivars show variability in the number of petals.
• The petals and sepals are usually fused.

Here are four flowers from the Solanaceae family.

You can observe this same characteristic: five petals fused at their base.

Fruits

• Usually a berry (e.g., Solanum sp.) or, more rarely, a capsule (e.g., Datura sp., Nicotiana sp.).

Pollinisation

Pollination is mainly entomophilous (by insects), particularly bees. Hummingbirds and certain fruit-eating birds (ornithophilous pollination) can also contribute to pollination.

For some species, such as tomatoes, the flowers require vibratile pollination to release the pollen. This is one of the reasons why bumblebees are used in greenhouse tomato cultivation. This is known as “buzz pollination.”

Is the potato (Solanum tuberosum) a Solanaceae?

Yes, indeed! Although we rarely look at the aerial parts of a potato plant, if we observe its flowers and fruits closely, we can see the same characteristics as in tomatoes (Solanum lycopersicum). Here are the flowers and fruit (a berry) of each of these two species.

Examples

Plantes alimentaires

• Tomato (Solanum lycopersicum)
• Potato (Solanum tuberosum)
• Eggplant (Solanum melongena)
• Bell pepper & Chili pepper (Capsicum spp.)

Medicinal or Potentially Toxic Plants

(Solanaceae are known for their powerful alkaloids, such as solanine, atropine, scopolamine, and capsaicin. These substances can have neurological, digestive, or analgesic effects.)

• Belladonna (Atropa belladonna) – Contains alkaloids such as atropine.
• Ashwagandha (Withania somnifera) – Contains alkaloids.
• Datura (Datura stramonium) – Hallucinogenic and toxic plant.
• Mandrake (Mandragora officinarum) – Formerly used in medicine and witchcraft.
• Tobacco (Nicotiana tabacum) – Nicotine
• Hot pepper (Capsicum spp.) – Capsaicin

Ornamental Plants

• Pétunia (Petunia spp.)
• Brugmansia (Brugmansia spp.)
• Solanum grimpant (Solanum jasminoides)
• Morelle faux jasmin (Solanum laxum)
• Nicotiana (Nicotiana alata)
• Coqueret du Pérou (Physalis peruviana)
• Datura (Datura spp.)

It is the flowers that determine whether plants belong to the Solanaceae family. These flowers are mostly pentamerous with a fused corolla and calyx and a characteristic arrangement of stamens around the pistil. While the flowers of Solanaceae are sometimes delicate and inconspicuous in some species, they can reach impressive sizes and display vibrant colors in others. From the ubiquitous tomato to the alluring petunia, the evil mandrake, and the exuberant brugmansia, Solanaceae are well represented in horticulture. Now it’s your turn to discover them!

In our next installment… the Cucurbitaceae!