Chilillo

Sometime in the 1760s or 1770s, a Spanish physician named Jose Celestino Mutis stripped bark from a tree in the Colombian highlands and tasted something sharp and peppery. He pressed a specimen, numbered it 3839, and shipped it across the Atlantic to the younger Linnaeus in Uppsala. That specimen became the type of Drimys granadensis, a cloud forest tree belonging to the Winteraceae, one of the most ancient flowering plant families on Earth. Mutis had arrived in New Granada in 1760 with a copy of Species Plantarum in his luggage and a proposal for a royal botanical expedition that would be ignored for two decades. The tree he collected was named and published before the expedition was even approved.

What distinguishes this cloud forest tree lies hidden in its wood. Unlike nearly all other flowering plants, Drimys granadensis lacks xylem vessels (the wide tubes most flowering plants use to move water) entirely, conducting water through tracheids alone (narrow cells that pass water through tiny pores). For more than a century this was considered proof that Winteraceae were living fossils, the least-specialized descendants of the first flowering plants. Molecular phylogenetics overturned that interpretation: Winteraceae sit among angiosperm clades that do have vessels, meaning the vesselless condition in Drimys is secondarily derived. Feild et al. (2002) proposed that as Winteraceae ancestors moved through temperate Southern Gondwana during the Early Cretaceous, freeze-thaw cycles selected against vessels because air bubbles formed in frozen water expand catastrophically upon thawing, destroying conductivity. Vessel-bearing wood loses up to 85% of its water-conducting capacity after a single freeze-thaw event; vesselless wood loses at most 6%. The tradeoff: vesselless wood conducts water at only about 20% the rate of vessel-bearing wood, which chains the species to habitats where moisture never fails.

Identification

Habit

Drimys granadensis is an evergreen tree or large shrub reaching 12-13 meters in height, though in elfin cloud forests near the treeline it may grow as a gnarled shrub only a few meters tall. Young branches are glaucous (covered with a pale waxy bloom) and reddish, giving the crown a distinctive reddish tint when seen from above. The bark is aromatic and intensely peppery to the taste, a character so prominent that the Greek name Drimys means "acrid" or "pungent." This peppery compound, polygodial, belongs to a class of sesquiterpenes called drimanes that give the entire genus its bite.

Leaves

The leaves are alternate, simple, and thick-textured, measuring 5-16 cm long by 1-5.5 cm wide. They are elliptic to oblong with an olive-green upper surface and a distinctly pale, glaucous underside, a reliable field character for separating this species from other montane trees. Secondary veins number 8-19 per side. The petioles are wrinkled and flattened. Crushed leaves release an aromatic scent. The stomata on the leaf underside are occluded by cutin plugs, a feature once thought to compensate for the species' poor hydraulics. Feild et al. (1998) overturned this interpretation, showing that the plugs instead maintain photosynthesis during mist events by preventing water films from covering the stomatal pores and blocking CO2 diffusion. In cloud forests where persistent mist is a daily occurrence, this adaptation is a significant advantage.

Flowers

Flowers appear in terminal or axillary clusters of 1-6 (sometimes up to 8), each with 2-3 sepals and 8-17 (sometimes up to 25) membranous petals ranging from white or creamy yellow to occasionally reddish. The petals are oblong to elliptic with yellowish glands. A distinctive feature of D. granadensis and its close relatives is the presence of large glands on the mature anther connective, formed from overgrowth of subepidermal oil cells. This shared trait (a synapomorphy) unites the "Northeastern Drimys clade," which includes D. granadensis, D. brasiliensis, D. angustifolia, and D. roraimensis.

Fruits

The fruits are berry-like, slightly curved (falcate), turning from green to dark purple or reddish-black when ripe. They contain multiple seeds embedded in fleshy, aromatic pulp. The dark, fleshy berries suggest bird dispersal (ornithochory), though no specific studies have documented which bird species feed on them.

Distribution

Drimys granadensis ranges from the highlands of southern Mexico through Central America and into the northern Andes as far south as Bolivia. GBIF records span 4,693 specimens across ten countries, with the strongest concentrations in Colombia (51%), Mexico (17%), and Costa Rica (14%). The species is strictly montane, occupying cloud forests, elfin forests at the highest elevations, humid oak and pine-oak forests (especially in Mexico), and paramo edges in Colombia. It favors riparian habitats and protected ravines where moisture is reliable.

In Costa Rica, the species occurs on every major highland area: the Cordillera de Talamanca (including La Amistad International Park, Cerro de la Muerte, and the Valle de Silencio), the Cordillera Central (Volcan Barva in Braulio Carrillo National Park, Volcan Poas), and the Cordillera de Guanacaste (Volcan Cacao). GBIF documents 677 records across 148 unique localities in all highland provinces. San Jose province holds the most collecting localities (42), followed by Heredia (23), Limon (23), and Guanacaste (13). In the Brunca region, 17 localities cluster mainly in the La Amistad Biosphere Reserve, including Cerros Tararias, the Valle de Silencio, and around Tres Colinas in Puntarenas.

Ecology

Pollination

The pollination system of Drimys granadensis reflects its deep evolutionary antiquity. Rather than specialized bee or hummingbird pollination, the flowers attract beetles (Coleoptera), flies (Diptera), and thrips (Thysanoptera), a generalist insect-pollination syndrome consistent with basal angiosperms. A study at Altos de Yerbabuena in the Sabana de Bogota (2,850 m) identified four beetle species and two fly species as primary pollinators, based on their abundance on flowers and the pollen loads they carried (Marquinez et al. 2009). Floral rewards include pollen and exudates on the stigma, connective, and base of the petals. Crab spiders of the genera Misumena and Thwaitesia (Thomisidae) use the flowers as ambush sites, preying on visiting insects (Marquinez et al. 2010).

Cloud Forest Hydraulics

Feild and Holbrook (2000) published a study of water transport in D. granadensis in a Costa Rican elfin cloud forest. Their most surprising finding was that the tree transpired more water at night than during the day, with nocturnal water loss accounting for about 50% of total daily transpiration. Wind speed, rather than sunlight, was the primary driver of water loss. The species' poor stomatal closure means it depends on consistently wet soils, making it acutely sensitive to changes in cloud forest hydrology. If rising temperatures push cloud bases upward, reducing mist precipitation, this tree is among the species most likely to suffer.

Ancient Herbivore Association

Larvae of Phyllocnistis moths (Gracillariidae) mine the leaves of D. granadensis in Costa Rica. This plant-moth association may be among the oldest known. The primitive moth genus Prophyllocnistis, in the same subfamily, feeds on Drimys in Chile, and structurally similar fossil leaf mines from Kansas and Nebraska date to 97 million years ago. If the fossil mines were indeed made by a relative of Prophyllocnistis on a relative of Drimys, this herbivore-plant relationship predates the extinction of the dinosaurs by 30 million years.

Taxonomic History

Drimys granadensis was described by Carl Linnaeus the Younger (L. f.) in Supplementum Plantarum 269 (1781[1782]), based on material sent to Uppsala by Jose Celestino Mutis from New Granada (colonial Colombia). The lectotype is Mutis 3839, held at the US National Herbarium (barcode US00104111), designated by A.C. Smith in his 1943 monograph "The American species of Drimys." The species epithet "granadensis" refers to Nueva Granada, the Spanish colonial territory encompassing modern Colombia, Ecuador, Venezuela, and Panama.

Linnaeus the Younger (1741-1783) succeeded his father as head of Practical Medicine at Uppsala at age 22, without exams or thesis defense. His Supplementum Plantarum incorporated approximately 700 new species drawn from his father's unpublished notes and from material sent by global correspondents. He died at 42, just a year after the work was published. Mutis (1732-1808), the collector, was a physician, naturalist, astronomer, and theologian from Cadiz who had arrived in New Granada in 1760 as private physician to the viceroy. Linnaeus the elder called him Phytologorum Americanorum Princeps, "Prince of American Plant Scientists." In 1801, Alexander von Humboldt spent over two months with the aging Mutis in Bogota, praising his collection.

The species has been shuttled between ranks throughout its taxonomic history. Eichler (1864) reduced it to a form of Drimys winteri in his treatment for Flora Brasiliensis; Dusen (1905) elevated it to a variety. The modern consensus, reflected in Kew's Plants of the World Online and supported by molecular data, treats D. granadensis as a distinct species. The two occupy largely non-overlapping ranges: D. winteri in the temperate forests of Chile and Argentina below 1,200 m, and D. granadensis in tropical montane forests from Mexico to Peru above 1,000 m. A.C. Smith's 1943 monograph recognized five varieties of D. granadensis: var. granadensis (Colombia), var. uniflora (Venezuela), var. mexicana (Mexico to Costa Rica), var. chiriquiensis (Panama), and var. peruviana (Peru).

The Winteraceae: A Gondwanan Relict Family

Winteraceae is a family of 93 species in five genera, distributed mostly across the Southern Hemisphere: Malesia, Oceania, eastern Australia, New Zealand, Madagascar, and the Neotropics. Drimys is the only genus in the Americas. The oldest fossils attributed to the family are pollen tetrads of Walkeripollis gabonensis from Gabon, dating to approximately 125 million years ago (late Barremian). By the Late Cretaceous, Winteraceae wood was present in Antarctica; by the Paleocene, their pollen reached Greenland. The family has since retreated to wet, cool refugia. The first reliable South American macrofossils, fossil wood of Winteroxylon, were described from the Eocene of Patagonia (Gandolfo et al. 2021), providing physical evidence for the biogeographic connections between South America and Australasia through Antarctica.

Similar Species

In Costa Rican cloud forests, D. granadensis co-occurs with oaks (Quercus), Weinmannia, and Podocarpus. The combination of aromatic peppery bark, glaucous leaf undersides, and reddish young stems separates it from all co-occurring species. The closest relative, Drimys winteri, is restricted to southern Chile and Argentina and does not overlap in range. The genus Drimys contains seven accepted species total; the three closest to D. granadensis are D. brasiliensis, D. angustifolia, and D. roraimensis, all South American and united by the shared presence of conspicuous glands on the stamen connective.

Uses and Chemistry

In Colombia, D. granadensis is known as "ají de páramo" (paramo pepper), valued for its sharp, peppery flavor derived from drimane sesquiterpenes rather than the capsaicin of true chili peppers. The bark is dried in the sun or ground into powder and used as a condiment. Contemporary Colombian gastronomy is rediscovering this ingredient as a distinctive highland spice. In Costa Rica, where the tree is called "chilillo" (little chili) or "palo picante" (spicy stick), the bark has been used for stomachache, toothache, and fever. The species is listed in Colombia's Vademecum de Plantas Medicinales for gastrointestinal ailments, kidney problems, and rheumatic disorders.

The essential oil chemistry of D. granadensis varies dramatically between populations, suggesting long genetic isolation. Costa Rican leaf oil (Ciccio 1997, CIPRONA, Universidad de Costa Rica) is dominated by monoterpenes (71.5%), led by 4-terpineol (21.9%) and sabinene (16.6%). Colombian leaf oil (Gaviria et al. 2011) shifts to sesquiterpenes (73.7%), with germacrene D (14.7%) as the major component. Ecuadorian populations (Cartuche et al. 2024) are also sesquiterpene-dominant but with a different profile, led by gamma-muurolene (10.6%) and spathulenol (10.1%). The Ecuadorian study also found moderate anticholinesterase activity, suggesting potential Alzheimer's disease applications, though the presence of safrole (~2%) warrants toxicity assessment.

Conservation Outlook

Drimys granadensis has not been formally assessed by the IUCN Red List, though Kew's Plants of the World Online classifies it as Least Concern based on a Colombian national assessment. The species appears common in suitable habitat across its broad range, and in Costa Rica it is protected within La Amistad International Park, Braulio Carrillo National Park, Volcan Poas National Park, and throughout the Cordillera de Talamanca.

The primary concern is the future of cloud forest itself. Rising temperatures are pushing cloud bases upward across the tropics, altering the mist precipitation that sustains these ecosystems. In Monteverde, Costa Rica, measured changes in cloud patterns are already affecting amphibian and bird populations. D. granadensis is particularly vulnerable because of its poor stomatal closure and dependence on consistently wet soils. A tree that transpires more water at night than during the day, as Feild and Holbrook documented, cannot tolerate even modest drying of its environment. Agricultural expansion, cattle grazing, and land-use change in montane zones compound the climate threat. The species' long-term future depends on the protection of intact cloud forest corridors, especially along the Cordillera de Talamanca, which connects populations across Costa Rica and Panama.