Capsicum regale

Overview

Capsicum regale is a wild forest pepper native to Colombia, Ecuador and Peru, found mainly along the eastern slopes of the Andes where montane forest meets the upper Amazon basin. It is not a cultivated chilli and does not resemble the familiar peppers grown for cooking. Its relatively open, slender shrub form supports pairs of very unequal leaves, small yellow flowers arranged in clusters, and berries that mature to a deep blue-purple rather than red or orange.

The purple fruiting stalks are as distinctive as the berries. They become upright, thick and fleshy as the fruit matures, and the persistent calyx beneath the berry is also vivid purple. Alongside the dark berries, these structures give the plant an appearance unlike most wild Capsicum. Its seeds are black, flattened and unusually large, and the ripe fruit is non-pungent.

The species was scientifically named in 2020, after study of Colombian plants collected on expeditions in 2016 and 2019. Earlier preserved specimens from Ecuador and Peru showed that the plant was more widespread than the original expedition site suggested. It belongs to the Andean evolutionary group of wild peppers and has 26 chromosomes, rather than the 24 typical of the main domesticated chilli species.

Scientific name

Capsicum regale Barboza & Bohs

Family

Solanaceae

Native countries

Colombia, Ecuador, Peru

Evolutionary group

Andean clade

Growth habit

Slender shrub, generally 1.8–2.5 m

Earliest examined collection

1989, Ecuador

Type specimen

22 August 2019, Colombia

Published name

20 November 2020

Flowers

Yellow, sometimes maroon-marked

Ripe berries

Dark blue to purple, 6–9 mm

Pungency

Non-pungent

Seeds

Black, flattened, C-shaped

Elevation

700–1,900 m

Chromosomes

2n = 26

Conservation

Preliminary Endangered (2020)

Discovery & naming

The story of Capsicum regale begins before it received a name. A specimen collected in Morona-Santiago, Ecuador, on 18 August 1989 is the earliest dated collection listed in its original 2020 description. Other material was gathered in Ecuador in 1998, 2001 and 2005, and a collection was made in the Kampankis range of northern Peru in August 2011. These plants were preserved or photographed without being recognised as the same distinct pepper species.

The breakthrough occurred during fieldwork in Caquetá, Colombia. On an expedition in April 2016, botanists encountered an unfamiliar nightshade shrub in wet forest near Florencia. Its long stamens, deeply separated yellow flower lobes, fleshy calyx projections and purple fruits were so unusual that even specialists in the nightshade family could not confidently place it in a genus. Some features recalled Cuatresia; others suggested Lycianthes. The research team gave it the temporary, playful working name “Cuatresianthes”, blending those possibilities.

Leaf samples were sent for DNA work in the laboratory of Lynn Bohs. Sequence comparisons instead placed the plant within the genus Capsicum, and subsequent analysis showed that it was not a previously described species. The researchers then searched herbarium material, including specimens that had been filed as unidentified Cuatresia, and connected the Colombian collections to the earlier Ecuadorian and Peruvian plants. This is an unusual example of a pepper being recognised through DNA evidence before its botanical identity had become obvious by appearance.

A later gathering on 22 August 2019, numbered Orejuela and colleagues 3034, was chosen as the reference specimen or holotype. It came from a steep forest path near a river on Finca de Don Isauro, Corregimiento El Caraño, municipality of Florencia, Caquetá, at about 1,004 metres elevation. The holotype was deposited in the COL herbarium in Colombia; the original account lists duplicate material for COAH, CORD and HUAZ.

Botanists Gloria E. Barboza and Lynn Bohs formally named the species Capsicum regale in a study authored with Carolina Carrizo García and Marisel Scaldaferro, published in PhytoKeys on 20 November 2020. The name comes from Latin regalis, meaning royal or regal. The authors chose it both for the plant's remarkable appearance and for the rich, royal-purple colour of its leaves' veins, fruiting stalks, calyces and berries.

The comprehensive 2022 monograph of wild and cultivated Capsicum retained C. regale as a distinct species, incorporated its description into an updated identification key, and placed it alongside the other members of the Andean group. Kew's Plants of the World Online also accepts the name.

Plant & foliage

The plant is a slender, sparsely branched forest shrub, generally between 1.8 and 2.5 metres tall, with smaller individuals near a metre and exceptional examples reaching about 3 metres. The main stem may measure roughly 8 mm across at its base. Its upper branches are relatively weak and often spread outward horizontally, sometimes forking into two. Young stems are smooth, shiny and pale green with lengthwise markings; older stems become dark brown and develop small lenticels.

One of the most conspicuous features is the pairing of strikingly unequal leaves, a pattern botanists call anisophylly. A major leaf typically measures 17–20 cm long and 4.7–8 cm wide, with some reaching 24 cm in length. It is elliptic, finely pointed, thin and soft in texture, and attached to a stalk usually 1.5–2.3 cm long. The much smaller companion is usually 2–5 cm long, only 1–3 cm wide, more egg-shaped and often almost unstalked.

The leaf surfaces are largely hairless. Upper faces are green; lower faces are paler and may show a striking purple central vein, with secondary veins appearing lilac or green. The leaf stalk itself can be green above and purple below. These colours are not a separate cultivated purple-leaf form; they are part of the wild species' documented appearance.

The large, thin leaf blades contrast with the relatively small flowers and berries. Together with the open branching pattern, they give C. regale the appearance of a forest understory shrub rather than a compact, sun-grown pepper bush. The paired leaves and delicate branching are especially useful recognition features before it bears fruit.

Flowers & calyx

Capsicum regale stands apart in the way it arranges its blossoms. Rather than holding only one or two flowers at a leaf joint, it produces an elongated cluster of five to thirteen flowers. The cluster is usually unbranched, but it can occasionally fork. As older flowers fall, small scars remain along the axis. This somewhat extended, occasionally forked flower arrangement is rare in the pepper genus and was highlighted by the original authors as a key distinction.

The slender flower stalks are around 12–14 mm long, often with two or three subtle angles, and stand upright or spread sideways. The flower itself is roughly 10 mm across. Its five lobes open into a deeply divided star, reaching 5–5.5 mm long, so the outline looks sharper and more open than the shallow bell-shaped flowers of many related wild peppers.

Flower colour varies from clear yellow to yellow with maroon or reddish-purple markings. On some flowers, the outside is marked more strongly, while the inside is greenish-yellow with maroon along the petal edges. This variation was documented in the original colour plate, which includes flowers both with and without noticeable dark markings. The petals have very small hairs along their margins, although the flower surfaces are otherwise largely smooth.

Five stamens extend prominently from the open flower. Their white filaments are unequal: most reach about 3–3.2 mm, while one can extend to 3.5–4.3 mm. The anthers are elliptic and can appear lilac or pale blue. The style is about 4.3–4.5 mm long, ending in a light-green stigma. The conspicuous stamens helped make the species confusing when it was first encountered in Colombia.

Behind the petals sits a thick, fleshy, cup-shaped calyx about 2–3 mm long. Its margin may carry four or five short projections, although these can sometimes be absent. The projections are unusually broad at the base, flattened from side to side and often bend backward. They are frequently purple and measure around 1–1.8 mm long. Unlike the fine, needle-like teeth of several other peppers, these can look like tiny triangular wings.

The combination of a many-flowered cluster, deeply pointed yellow corolla, prominent pale stamens and fleshy purple-tinged calyx provides a distinctive set of features even when the characteristic ripe berries are absent.

Fruit & seeds

The berries are small, round and approximately 6–9 mm across. Their ripening sequence is particularly unusual. They begin green, pass through an almost white, translucent-looking stage, and finish dark blue to rich purple. The dark mature colour is very different from the red, orange or yellow fruits commonly associated with wild peppers.

These berries are non-pungent. The original researchers tested immature and mature fruits during their field study, and the botanical description specifically reports the absence of chilli heat. The berry wall is opaque in mature material, with a smooth inner lining and without the enlarged internal cells found in some other Capsicum fruits.

Much of the visual effect comes from the fruit base. The flower stalk changes from thin and greenish-purple into an upright, thickened, fleshy, brilliant dark-purple pedicel roughly 18 mm long. It widens toward the berry, while the mature calyx becomes a purple disk around its base. At the join between calyx and swollen stalk there is a noticeable ring-like narrowing. This small constriction is one of the characters botanists use in species identification.

Each fruit typically contains 7–17 black seeds. They are flattened, C-shaped and relatively large for such a small berry: about 2.7–3.4 mm long and 2.2–2.7 mm wide. Unlike the yellowish, lightly sculptured seeds of many domesticated peppers, these have a largely smooth seed coat and small spine-like projections around the margin, visible in magnified photographs.

That seed structure provided another important clue when distinguishing the species from Capsicum longifolium. The original authors examined seeds by scanning electron microscopy, allowing the subtle ridges and marginal projections to be described more precisely than they can be seen with the naked eye.

Range & habitat

The documented native range extends along the eastern Andean slopes of southern Colombia, eastern Ecuador and northern Peru, in a transition zone often called the Andean–Amazonian piedmont. This is where mountain slopes descend into the humid upper Amazon basin, creating a series of wet forest habitats across different elevations.

In Colombia, the principal specimens come from Caquetá, including forest around Florencia and San José del Fragua. In Ecuador, collections are documented from Morona-Santiago, Napo and Sucumbíos. In Peru, the original account cites Loreto, including the Kampankis mountain range near the border with Ecuador. The pattern crosses national boundaries but follows broadly similar humid forest conditions.

Plants have been recorded at approximately 700–1,900 metres above sea level. They grow in small populations in the understory of premontane and montane humid tropical forest, usually under the canopy rather than in exposed agricultural fields. The reference collection was made on a steep, forested path near a river, a setting consistent with the species' general preference for humid mountain-forest conditions.

These forests form part of one of the richest areas for wild pepper diversity. Across the Andean slopes, changes in elevation, moisture, vegetation and geography produce markedly different habitats over short distances. For C. regale, the evidence points to a forest species with a discontinuous recorded distribution, not a pepper that is broadly grown or transported between the three countries.

Herbarium and field records document both flowers and berries in April and from August through December. These are dates on which collectors found reproductive plants in their native habitats, not a guarantee that every population flowers only during those months.

See the original distribution map (Figure 4) and the USDA GRIN regional records.

Field collections & research history

The preserved records are unusually useful for reconstructing this species' history. In eastern Ecuador, the oldest listed collection was made by H. van der Werff and E. Gudiño along the Méndez–Morona road in August 1989, at around 800 metres. A 1998 collection came from the Antisana reserve region in Napo, and later specimens were collected near Jatun Sacha and in Sucumbíos. These earlier records helped demonstrate that the plant encountered in Colombia was not confined to one newly discovered patch of forest.

A specimen from Loreto, Peru, collected in August 2011 by I. Huamantupa, came from the Kampankis range near the international border. Together, the Colombian, Ecuadorian and Peruvian material showed that C. regale had been overlooked as a distinct species rather than simply appearing for the first time in 2019.

The Colombian collections, including material from 2015, 2016, 2017 and 2019, were particularly important because researchers saw live plants at several stages. Photographs captured the flower's variable maroon markings, the small white transition phase of fruit ripening and the final deep-purple berry. Fresh material also made it possible to examine the unusual calyx, measure the flower parts, test fruit pungency and count chromosomes.

The original research combined field photography, herbarium comparisons, microscope examination of seeds, chromosome preparation and DNA analysis. Rather than relying on a single remarkable image, the authors built the species description from several independent kinds of evidence and illustrated both the plant's visible features and its microscopic structures.

DNA & chromosomes

The first molecular comparison was decisive: DNA sequences from the Colombian material identified the unfamiliar nightshade as a member of Capsicum. The team subsequently compared sequences from four genetic regions, three from the chloroplast and one nuclear gene, against other peppers and related plants. Its placement in the Andean clade was strongly supported in the analyses published in 2020.

Its chromosome count was established directly from root tips of germinated seeds collected in Colombia. Researchers examined cells from three seedlings and reported 2n = 2x = 26, meaning thirteen pairs of chromosomes. This is consistent with the Andean group of wild Capsicum. In contrast, the best-known cultivated species, including C. annuum, C. chinense and C. baccatum, generally have 24 chromosomes.

Within the Andean group, the 2020 DNA results placed C. regale near C. rhomboideum and C. hookerianum, although the finer branching order was less secure. The study recovered a possible closer relationship to C. rhomboideum, but reported weak statistical support for that exact pairing. Such uncertainty matters: plants that look most alike are not always the nearest relatives in a DNA-based evolutionary tree.

Capsicum longifolium was the most useful comparison based on physical appearance, but it is not simply another form of C. regale. The authors distinguished them using the combined evidence of leaves, calyx texture, flower shape, purple fruit stalks, berry colour and seed structure. The broader 2022 monograph retained those distinctions when revising the genus.

This research changed the understanding of diversity in the genus by showing that even a strikingly unusual plant, initially thought to fall outside Capsicum, could belong to one of its established wild lineages. It also showed the value of revisiting previously unidentified herbarium collections once a new species has been recognised.

Identification & related species

The strongest identification combination is large, unequal, hairless leaf pairs; an elongated cluster of five to thirteen flowers; deeply star-shaped yellow flowers; thick, flattened calyx projections; and upright, swollen purple stalks carrying dark blue-purple berries. Its black C-shaped seeds add another confirmation when mature fruit is available.

Compared with Capsicum longifolium

This is the closest visual comparison in the original description. Both are Andean wild peppers with yellow flowers, little hairiness, many-flowered clusters and black seeds. But C. longifolium has much narrower, elongated leaves, less fleshy calyces, a less deeply divided flower, and green fruiting stalks bearing orange berries. By contrast, C. regale has broadly elliptic major leaves, occasional forked flower clusters, deep-star corollas, thick purple stalks and dark blue-purple fruit.

Compared with Capsicum dimorphum

C. dimorphum can also have yellow flowers, paired leaves and black seeds, but is generally hairier, usually has smaller main leaves, and commonly bears one to five flowers in an unbranched cluster. Its mature berries are generally orange to red, not blue-purple. Its calyx projections are also shorter or sometimes absent rather than forming the distinctive fleshy purple structures of C. regale.

Compared with Capsicum rhomboideum and C. hookerianum

These species have appeared near C. regale in molecular analyses, but look quite different. C. rhomboideum usually has bell-shaped yellow flowers, a hairier plant surface and bright red or orange fruit; C. hookerianum has shorter, bell-shaped yellow flowers and a ring of long calyx projections around its red berries. Neither has the same combination of broad unequal leaves, deeply divided corollas and uniformly royal-purple fruiting structures.

These comparisons are why the purple berry is an excellent starting clue but should not be the only trait used. Leaf shape, flower arrangement, calyx structure and seeds together establish the species more reliably.

Conservation

The scientists who described Capsicum regale in 2020 proposed a preliminary Endangered (EN) assessment under IUCN criterion B2ab(iii). They estimated an extent of occurrence of about 47,806 km², the wider area bounded by known sites, but an area of occupancy of only 32 km², based on the small number of documented occupied grid cells. The two numbers describe different measures and should not be confused.

The concern arose from small, scattered populations and continuing damage to the forest habitat. The original authors pointed to deforestation, fragmentation and a decline in habitat quality, especially in areas affected by agricultural expansion. Some collections fall within or near protected areas, but that does not remove pressure on forest outside those boundaries.

The Endangered category is a scientific assessment proposed in the 2020 paper, not a claim that this page has independently verified a formal IUCN Red List listing. Kew also displays a 2024 computer-model prediction of “not threatened” from a separate global plant-risk project. That automated prediction is a different kind of evidence and does not overturn the field-based 2020 proposal by itself.

Protection of the moist Andean–Amazonian forest is important for preserving the species, including its unusual purple berries and flowers, and for retaining wild genetic diversity across the pepper genus. Continued field surveys could reveal additional populations and improve the geographic information used in future conservation assessments.