Capsicum caballeroi

Overview

Capsicum caballeroi is a naturally occurring wild pepper found only in Bolivia. It grows in shaded mountain forests rather than in cultivated fields, often beside moist ravines and near forest edges. While its flowers and fruit clearly mark it as a Capsicum, its woody growth and distinctive yellow, bell-shaped blossoms give it a different appearance from familiar cultivated chillies.

It is an accepted species recognised by the Royal Botanic Gardens, Kew. A detailed 2022 scientific review places it within the Bolivian group of wild Capsicum species, which includes several relatives restricted to the tropical Andes and nearby forests.

Native range

Bolivia

Classification

Wild species

Growth habit

Shrub or small tree

Flowers

Yellow, bell-shaped

Ripe fruits

Bright red, pungent

Published name

2006

Discovery and naming

The species was formally described by American botanist Michael Nee, with the name published on 28 December 2006 in the journal Brittonia. Botanical collections predate that publication. A preserved specimen held by the Field Museum was collected in Santa Cruz in May 1992, while the official type collection was made in April 1994 by I. Vargas C. and J. M. Camacho.

That type specimen came from Cerro Bravo, north of Comarapa, in Amboró National Park, at approximately 2,400–2,500 metres above sea level. These carefully documented specimens allowed researchers to establish the species as distinct from other wild Bolivian peppers.

The name caballeroi honours Israel Gerardo Vargas Caballero, a Bolivian botanist whose investigations and those of his students helped document the country's wild and cultivated plants. The original description also refers to Manuel María Caballero Province, where many specimens were found.

Plant and foliage

Unlike a typical garden chilli, C. caballeroi may form a substantial woody shrub or occasionally a small tree. The 2022 monograph reports plants commonly between 70 centimetres and 5 metres tall, with exceptional specimens approaching 7 metres. Older branches become brown or grey-brown, and the main stem can thicken considerably with age.

The foliage is generally firm and slightly leathery. Leaves often grow in pairs at branching points, with one noticeably larger than the other. Major leaves are broadly elliptic, around 4–13.5 cm long, and taper towards a pointed tip. Their surfaces are usually smooth, sometimes with sparse, short hairs along the underside of the main vein.

Flowers usually emerge singly or in pairs from the leaf axils, each suspended from a slender stalk. This open arrangement gives flowering branches a delicate appearance despite the plant's woody structure.

Flowers and fruit

The flowers are among the easiest ways to recognise Capsicum caballeroi. Their corollas are entirely yellow to lemon-yellow, with a narrow bell-shaped tube and five short, backward-curving lobes. Flowers are commonly around 11–14 mm long and hang from stalks approximately 20–40 mm long.

At the base of the flower is an unusual green calyx with ten unequal pointed appendages: five longer and five shorter. This detail is especially useful for telling the plant apart from closely related wild peppers whose calyces have fewer, more uniform points.

The berries are rounded and sometimes slightly flattened at the top. They begin pale green or whitish and mature to bright red, usually measuring about 10–16 mm across. Ripe fruits hang from long, curved stalks and contain relatively large, pale yellow to almost white seeds.

The fruits are pungent, so this wild species produces genuine chilli heat. Its botanical descriptions establish pungency, but they do not provide a reliable standard Scoville measurement. The 2022 monograph describes 5–21 seeds in an individual berry.

Habitat and distribution

C. caballeroi is endemic to central Bolivia, with documented collections in Santa Cruz, Cochabamba and Chuquisaca. It is associated particularly with montane cloud forests and the Yungas and Bolivian Tucumano montane forest vegetation regions.

Researchers report it from 1,000–2,600 metres above sea level, often in moist, shaded, wooded ravines or at forest margins. These are comparatively humid mountain habitats, very different from the exposed, hot conditions in which many growers keep cultivated peppers.

Field observations suggest it may flower and fruit across much of the year. The 2022 review notes particularly frequent flowering from November to early January and fruiting from January to June. Those periods describe observations in its native range rather than a fixed calendar for cultivated plants.

Relationship to other wild peppers

Botanical and genetic studies place Capsicum caballeroi within the Bolivian clade of the genus. Its reported chromosome number is 2n = 24, a count shared with many—but not all—members of Capsicum.

It resembles the Peruvian wild species C. piuranum, particularly in its yellow tubular flowers. However, C. piuranum has a calyx with five more uniform appendages, darker seeds and fruits described as non-pungent. C. caballeroi has ten unequal appendages, pale seeds and pungent red fruits.

It also grows in some of the same Bolivian regions as C. minutiflorum. Both have yellow flowers and red berries, but C. minutiflorum has generally smaller flowers and fruit, thinner leaves and a calyx with only five main appendages. These details help botanists identify wild plants in the field and in preserved collections.

Conservation and local names

The 2022 monograph gave C. caballeroi a preliminary Vulnerable assessment, using the criteria VU B1ab(ii,iii). The researchers described small, scattered populations and declines in suitable habitat associated with ongoing deforestation. This is the assessment published by those authors, not confirmation of a separate official IUCN Red List classification.

Much of its documented range lies within Amboró National Park and surrounding forests, but protection within a park does not eliminate pressures on adjoining habitat. The species therefore represents not only a distinctive wild pepper but also a part of the region's threatened mountain-forest biodiversity.

Recorded local names include aribibi in Cochabamba, ají de monte in Santa Cruz and ulupica de yunga in Santa Cruz. These names show that people in Bolivia have recognised the plant within their wider landscape of wild peppers. The 2022 monograph does not document a specific established culinary use for this species.