Capsicum ceratocalyx

Overview

Capsicum ceratocalyx is a wild shrub confined to Bolivia. Botanists have documented it in the Yungas, the humid forests along the eastern side of the Andes. It is a separate species, not a cultivated pepper variety, and its identification relies heavily on details of its flowers and stalks.

The most distinctive feature is the combination of three to five strongly inward-curving calyx projections and angled, wing-like ridges along the fruit stalks. The flowers are yellow, while the small rounded fruits mature to red. These features make the species especially recognisable in botanical descriptions.

Native range

Bolivia

Family

Solanaceae

First described

2006

Plant type

Wild shrub

Habitat

Yungas montane forest

Recorded height

0.8–3 metres

Discovery & scientific name

American botanist Michael Nee formally described Capsicum ceratocalyx in 2006 in the journal Brittonia, in a paper with Lynn Bohs and Sandra Knapp on new Bolivian nightshade species. The original specimen was collected on 10 May 2001 near Huancané in the Sud Yungas area of La Paz, at approximately 2,225 metres above sea level.

Other herbarium collections had existed before the species received its name. The description brought together those specimens and showed that the plant was different from wild Bolivian peppers it had previously been compared with.

The name ceratocalyx refers to the horn-like projections of its calyx—the small cup of tissue immediately behind the flower. They are more than a decorative feature: their shape is one of the clearest ways to identify this species.

Plant & foliage

Botanical descriptions record an upright shrub roughly 80 centimetres to 3 metres tall, with much of its branching toward the upper part of the plant. Young stems are green and angled, sometimes bearing very short fine hairs. Older stems develop brown bark.

The leaves are noticeably firm and leathery, an important contrast with the thinner leaves of several other wild peppers. They are green, generally elliptic to lance-shaped and arranged in pairs that may differ in size. Their relatively smooth surfaces and marked veins are visible in recent field photographs.

The photograph shows a developing green berry; it should not be mistaken for the colour of a fully ripe fruit.

Flowers & the horned calyx

The plant produces small yellow flowers in clusters arising near the leaves. Wild Capsicum species can vary considerably in flower arrangement; C. ceratocalyx is among those capable of forming crowded groups with numerous flowers along a short flowering axis. After individual flowers fall, their stalk attachments can remain visible.

Its calyx has three to five thick projections that bend inwards or spread from the base of the flower. The unusually prominent projections explain the scientific name, but the stalks are just as important. Flower stalks are slightly ridged; as fruit develops, these ridges become conspicuous wings running along the stalk.

This is an uncommon combination within the genus. The 2022 monograph uses the calyx and winged stalks repeatedly in its identification keys, because together they distinguish this pepper from other wild Andean species.

The detailed botanical drawing of the flowers, calyx, fruit and seeds is Figure 44 in the 2022 Capsicum monograph, illustrated by P. Peralta.

Fruit & seeds

The fruit is a small, roughly spherical berry measuring approximately 6–8 millimetres across, though some specimens are slightly smaller. It develops green, can darken through brownish tones while immature, and becomes bright red when ripe.

The 2022 scientific treatment describes the fruit as pungent. That places it among the hot wild peppers, although it is not a cultivated variety with a standard Scoville rating. Each berry contains small, curved seeds, and the thick-walled fruit is held on an upright, distinctly ridged stalk.

For botanical identification, the shape of the stalk and the persistent horned calyx are more dependable features than fruit colour alone: many unrelated wild peppers also produce small red berries.

Habitat & distribution

Capsicum ceratocalyx is endemic to Bolivia, with recorded specimens from La Paz and Cochabamba departments. The older type collections focused on the Nor Yungas and Sud Yungas regions of La Paz; later research expanded the documented range eastward.

Botanists have found the species in moist, relatively undisturbed montane forest between approximately 700 and 2,500 metres elevation. The Yungas form a humid transition between high Andean mountains and lower tropical forests, where steep slopes and changing elevation create many specialised plant habitats.

Published specimens record flowering and fruiting between November and July. These are field observations from its natural range, not a fixed garden-growing calendar.

Its place among wild peppers

Earlier genetic studies placed C. ceratocalyx with a group of mostly Bolivian wild peppers that includes C. minutiflorum, C. coccineum and C. caballeroi. Its similarity to some of those plants had also caused confusion in older herbarium identifications.

More extensive DNA research published in 2022 found that C. ceratocalyx occupied a more isolated position on the wider Capsicum family tree, rather than sitting securely inside the core Bolivian group. Its precise evolutionary relationships are therefore more interesting than a simple species-to-species comparison suggests.

Its botanical traits remain distinctive regardless of the genetic grouping: leathery leaves, yellow flowers, horn-like calyx projections and winged fruit stalks form an unusual combination.

Conservation

Capsicum ceratocalyx is known from relatively few botanical collections and a geographically limited area. In the 2022 monograph, researchers calculated an estimated extent of occurrence of approximately 3,612 km² and an area of occupancy of 32 km².

On that evidence, the authors gave it a preliminary Endangered assessment under IUCN criteria. Their concern centres on the continuing loss and alteration of Yungas forest as farming expands. This is the assessment published by the researchers, not a claim that an independent official IUCN Red List entry has been verified.

As with many narrowly distributed wild pepper species, protecting the forest where it grows also protects genetic diversity that is not represented by familiar cultivated chillies.