Limoncillo facts for kids

Esenbeckia runyonii is a type of flowering tree that belongs to the citrus family, called Rutaceae. It grows naturally in northeastern Mexico. You can also find a small, separate group of these trees in the Lower Rio Grande Valley of Texas in the United States.

People often call this tree Limoncillo or Runyon's Esenbeckia. Its scientific name honors Robert Runyon, a botanist and photographer from Brownsville, Texas. He found the first official sample of this tree in 1929 near Resaca del Rancho Viejo, Texas. Conrad Vernon Morton from the Smithsonian Institution then officially described the species in 1930. Some experts think it might be the same species as E. berlandieri.

What Runyon's Esenbeckia Looks Like

Runyon's Esenbeckia is a small tree that often has many trunks. It grows slowly, reaching about 9 meters (30 feet) tall and 0.6 meters (2 feet) wide.

Its leaves are dark green and shiny. Each leaf is made up of three smaller parts called leaflets, and each leaflet is about 2.5 to 7.6 centimeters (1 to 3 inches) long. The bark of the tree is mostly whitish. It has patches that are copper-colored, which peel off to show greenish bark underneath. This inner bark has small dots called lenticels, much like American sycamore trees.

The tree's flowers are white and shaped like stars, about 0.6 centimeters (0.25 inches) wide. They have four or five sepals (small leaf-like parts under the petals), the same number of petals, and an equal number of stamens (the parts that produce pollen). These flowers grow in wide clusters at the ends of branches. The tree blooms twice a year: once in late spring and again in September.

The fruit of the tree is a thick, woody capsule about 2.5 centimeters (1 inch) long. It has five sections called carpels. When the fruit is ripe, these sections break open to release black seeds, which can be up to 0.8 centimeters (1/3 inch) long. Green fruits have a strong orange smell, while the leaves smell like lemons.

Where Runyon's Esenbeckia Grows

Most E. runyonii trees are found in northeastern Mexico. This includes the states of Nuevo León, Tamaulipas, San Luis Potosí, and northwestern Hidalgo. They often grow on rocky slopes in deep, protected canyons. These areas are usually high up, between 610 and 914 meters (2000 and 3000 feet) in the Sierra Madre Oriental mountains. You can also find them where the Tamaulipan matorral (a type of shrubland) meets the forests in canyons.

A small number of these trees also grow in the Tamaulipan mezquital area of the Lower Rio Grande Valley in Texas, United States. They are found along resacas, which are old river channels. Scientists think this separate group of trees might have started from seeds carried by flooding from the Rio Grande river's drainage basin in the Sierra Madre Oriental.

How People Use Runyon's Esenbeckia

Farmers in Mexico use branches from Limoncillo trees to make living fences. They plant the cut branches in the ground during the dry season, and these branches eventually grow roots and become new trees, forming a natural fence. Because of its pretty leaves and flowers, it is also a nice ornamental plant for gardens.

See also

In Spanish: Mamón para niños