Stenophylla and other wild relatives
Wild coffee species beyond arabica and robusta, such as stenophylla and two East African species, carry heat tolerance and distinct flavours that breeders may need. Most wild species are threatened, and many are held in no genebank.
Across the chain: Sustainability · Science
Contents
In brief
- *Coffea stenophylla*, a West African species, grows wild at a mean annual temperature 6.2–6.8 °C higher than arabica.1
- In sensory panels, 81% of 15 judges said a stenophylla sample was arabica.1
- *C. racemosa* and *C. zanguebariae*, two East African species, combine heat tolerance with a low rainfall need.3
- A 2019 assessment found at least 60% of wild coffee species threatened with extinction.4
- Coffee seeds tolerate only partial drying and cannot be stored with conventional seed-bank methods.4,6
Coffee beyond two species#
Almost all coffee comes from two species, arabica (Coffea arabica) and robusta (C. canephora). The genus holds many more, most of them wild and never farmed (see The coffee genus). Botanists call the wild species that can pass genes to a crop its crop wild relatives. A 2019 study ranked wild coffee species in priority groups by how readily their genes reach the crop.4
Wild species matter for three reasons. Some tolerate heat or drought. Some resist pests and diseases. Some were once drunk as coffee and may taste good.2,3 According to a coffee science textbook, C. liberica, C. racemosa, C. stenophylla and C. humblotiana were cultivated for local production and consumption.9
Liberica and excelsa have their own entry. C. eugenioides, one parent of arabica, also has its own entry: Coffea eugenioides.8 This entry covers the others.
Stenophylla, the narrow-leaved coffee#
C. stenophylla was described in 1834. Its name refers to its narrow leaves, and its fruits are black, while most coffee species have red fruits.2 It is a small tree, native to Guinea, Sierra Leone and Ivory Coast.2 In its native habitat it grows in hot lowlands, at about 400 m.1
In the 19th century it was farmed on a small scale in Upper West Africa. Its seeds left Sierra Leone from at least the 1850s as “Sierra Leone coffee”. Seed reached Kew in 1894 and was sent on to India, Sri Lanka, Trinidad and Java.2 Small seeds and low yields kept it from becoming a lasting crop in Uganda, and low yields limited its wider uptake.2 By 2020 it was rare in the wild and no longer farmed.2
Fieldwork rediscovered it in Sierra Leone, where it had not been recorded in the wild since 1954.2 A 2021 study then tested its flavour and its climate. Its sensory profile resembled high-quality arabica. It grows where the mean annual temperature is 6.2–6.8 °C higher than for arabica.1
How stenophylla tasted#
Fifteen judges on four panels tasted stenophylla beside two arabica coffees and one robusta. The stenophylla came from a collection on Réunion and was originally from Ivory Coast.1 Asked whether each sample was arabica, 81% of judges said yes for stenophylla. For the robusta, 7% said yes.1
A separate sample, wild-collected in Sierra Leone, was cupped with the Specialty Coffee Association (SCA) protocol. The panel leader gave a consensus score of 80.25, just above the 80-point line for specialty coffee.1 Judges noted natural sweetness, medium-high acidity, fruitiness and good body. Tasting notes included peach, blackcurrant, mandarin, honey, black tea and jasmine.1
Hot-climate coffees from East Africa#
Two related species grow in the dry lowlands of East Africa. C. racemosa is native to central and southern Mozambique, eastern Zimbabwe and KwaZulu-Natal in South Africa. C. zanguebariae is native to southern Tanzania, northern Zimbabwe and northern Mozambique.3 Both are deciduous, although in some places they keep their leaves through the dry season.3
Their fruits ripen fast. In C. zanguebariae, flowering to harvest takes around 4 months, against 6–8 months in arabica.3 Both are farmed on a very small scale: C. racemosa in KwaZulu-Natal, South Africa, and C. zanguebariae on the Ibo and Quirimbas islands and near Pemba, Mozambique.3 Their yields are low compared with arabica and robusta.3
The chart compares the mean temperatures where these species grow wild.
Data table
| Point | °C | Source | |
|---|---|---|---|
| Arabica (C. arabica) | 18–20 reported | 18–20 | 1 |
| Arabica (C. arabica) | 18.7 modelled | 18.7 | 1 |
| C. racemosa | 22.9 modelled | 22.9 | 3 |
| Robusta (C. canephora) | 24–26 reported | 24–26 | 1 |
| Robusta (C. canephora) | 23.7 modelled | 23.7 | 1 |
| Liberica (C. liberica) | 23.9 modelled | 23.9 | 1 |
| C. zanguebariae | 24.8 modelled | 24.8 | 3 |
| Stenophylla (C. stenophylla) | 25–26 reported | 25–26 | 1 |
| Stenophylla (C. stenophylla) | 24.9 modelled | 24.9 | 1 |
Extinction risk and conservation#
A 2019 study assessed every coffee species then known, 124 in all, against the International Union for Conservation of Nature (IUCN) Red List criteria. At least 60% were threatened with extinction. Some 45% were held in no germplasm collection, and 28% were known from no protected area.4
Data table
| species | Source | |
|---|---|---|
| Critically Endangered | 13 | 4 |
| Endangered | 40 | 4 |
| Vulnerable | 22 | 4 |
| Not threatened (NT or LC) | 35 | 4 |
| Data Deficient | 14 | 4 |
Stenophylla is threatened with extinction in the wild and listed as Vulnerable.1,5 C. zanguebariae is listed as Vulnerable and C. racemosa as Near Threatened.5 In Guinea, Sierra Leone and Ivory Coast, stenophylla and C. affinis are threatened by forest loss.2
Conserving coffee outside the wild is hard. Coffee seeds cannot be stored with conventional seed-bank methods.4 They survive partial drying but not complete drying.6 So collections are kept mostly as living trees in field genebanks.10 Living collections are costly, and open pollination puts the genetic integrity of species at risk.4 How seeds lose viability is covered in Seed anatomy and storage.
Access to wild material is regulated. The Nagoya Protocol, in force since October 2014, requires Prior Informed Consent from the country that provides genetic resources.7
Stenophylla and its climate#
The 2021 study compared reported climate data from the literature with values modelled at cleaned wild occurrence records. For stenophylla, the reported mean annual temperature is 25–26 °C, with 1,500–2,650 mm of rain a year. The modelled values are 24.9 °C and 2,288 mm.1 For arabica, the reported mean is 19.0 °C (18–20 °C) and the modelled mean 18.7 °C. Robusta is adapted to 24–26 °C; liberica was modelled at 23.9 °C.1 The difference from arabica is 6.8 °C on reported and 6.2 °C on modelled data.1
The modelled set for stenophylla is small: 20 records before cleaning and 12 after duplicates within 1 km were removed.1 These values describe where wild plants occur, not where they crop best. For robusta, a revised estimate puts the optimum lower than occurrence and literature values suggest1 (see Coffea canephora).
Caffeine differs by provenance. Stenophylla from Sierra Leone has 0.9–1.9% caffeine (dry matter basis); samples from Ivory Coast have 2.05–2.64%.1
The sensory trials in detail#
The four panels used a CIRAD sensory protocol derived from ISO 6668 and ISO 13299, run between mid-2020 and early 2021. Beside the stenophylla from the Réunion collection, the panels tasted arabica from Ethiopia and Brazil and robusta from Indonesia.1 The share of judges who called each sample arabica was 98% for the Ethiopian arabica, 81% for stenophylla, 44% for the Brazilian arabica and 7% for the robusta.1 The single SCA cupping of the wild Sierra Leone sample gave 80.25 points.1
The trials are small. One panel score and 15 judges cannot show how stenophylla performs across sites, harvests and processing. No study opened for this entry measured stenophylla yields under modern farm conditions.
C. affinis, the other forgotten crop#
C. affinis is closely related to stenophylla. Both are small trees with obovate leaves, two to four flowers per leaf axil, six- to eight-parted flowers and black or black–purple fruits; C. affinis has larger, broader leaves.2 It was long thought to be a hybrid of C. liberica and C. stenophylla. The 2020 study rejects that: C. affinis is fertile and productive, its fruits are black rather than purple, and its DNA markers do not alternate between parents as hybrid markers do.2
It was last seen in the wild in 1941, until a 2015 herbarium specimen from Guinea and the 2020 fieldwork in Sierra Leone found it again.2 It has not been recorded in coffee research collections since the early 20th century.2 Its Red List category is Data Deficient.5
C. racemosa and C. zanguebariae in detail#
DNA sequences and morphology confirm that C. racemosa and C. zanguebariae are two distinct but closely related species.3 The 2021 climate profile used 50 records for C. racemosa and 20 for C. zanguebariae, with CHELSA climate data at a 1 km grid.3
| Species | Mean annual temperature | Annual rainfall | Elevation |
|---|---|---|---|
| C. racemosa | 22.9 °C3 | 807 mm3 | 200–600 (–780) m3 |
| C. zanguebariae | 24.8 °C3 | 998 mm3 | 100–380 (–680) m3 |
| C. arabica (same study) | 18.7 °C3 | 1,614 mm3 | – |
| C. canephora (same study) | 23.7 °C3 | 1,596 mm3 | – |
Values are modelled means at wild occurrence records. The study names heat tolerance, a low rainfall need and strongly seasonal rainfall as the useful traits, and judges them best accessed through breeding.3 Its sensory assessment applied no scores; dry-aroma notes were spice, sweet herbs and liquorice for C. racemosa, and herbal, light eucalyptus and liquorice for C. zanguebariae.3 A 1956 report, as cited in the study, describes C. racemosa as low in caffeine.3
Wild species in breeding#
Crossing species is possible across all the major groups of key African Coffea species.2 Diploid interspecific hybrids are usually sterile. Fertility, and with it yield, returns once the hybrid is converted to the tetraploid state (4n = 44), which makes it usable for transferring traits.2 Two examples: leaf-rust resistance in arabica from C. canephora × C. arabica, and leaf-miner resistance from C. arabica × C. racemosa.2 How a hybrid became arabica itself is covered in Polyploidy and the arabica genome.
The 2020 study sees two routes for stenophylla and C. affinis: breeding programmes, or minimal domestication by selecting trait-specific plants. It judges the second probably feasible only for high-value markets.2 According to the textbook chapter, wild species vary in caffeine, trigonelline and sucrose, a source of genes for breeders, although the biochemical and genetic basis of quality is not yet well enough understood to use them.9
Seed storage and genebanks#
All Coffea species produce intermediate seeds, which cannot survive complete drying but vary widely in how much drying they tolerate.6 Among ten species tested in 2000, including stenophylla, C. liberica and C. humilis were the most sensitive to drying and C. pseudozanguebariae the most tolerant; sugar content did not explain the differences.11
According to the Crop Trust summary of the global conservation strategy, most coffee accessions are kept in field collections, and cryopreservation or other back-up methods should be explored.10 The 2019 study calls coffee species difficult, expensive and risk-laden subjects for conservation outside the wild.4 Stenophylla is held in research collections, including those of the Centre National de Recherche Agronomique (CNRA) in Ivory Coast and the Institut de recherche pour le développement (IRD).2 The 2020 study calls for genotyping of these collections to check what they really hold; three accessions in Sierra Leone labelled C. affinis or arabica appear to be C. liberica × C. stenophylla hybrids.2
Access and benefit sharing#
The Nagoya Protocol came into force in October 2014. Using genetic resources from a country requires Prior Informed Consent (PIC) from its government and Mutually Agreed Terms (MAT), which set out benefit sharing.7 Material collected before the 1992 cut-off of the Convention on Biological Diversity is in theory not covered, but some institutions apply the rules to all samples.7 The Coffea Biological Resource Centre on Réunion holds over 700 genotypes from African countries and Indian Ocean islands and follows the Protocol voluntarily.7 The 2024 review warns that some researchers may move to fields without these hurdles.7 The Ethiopian case is covered in Ethiopian landraces.
Reference values#
| Parameter | Value | Source |
|---|---|---|
| Stenophylla, mean annual temperature (reported) | 25–26 °C | Davis et al. 20211 |
| Stenophylla, mean annual temperature (modelled) | 24.9 °C | Davis et al. 20211 |
| Stenophylla, rainfall (reported · modelled) | 1,500–2,650 mm · 2,288 mm | Davis et al. 20211 |
| Arabica, mean annual temperature (reported · modelled) | 18–20 °C · 18.7 °C | Davis et al. 20211 |
| Temperature gap, stenophylla minus arabica | 6.2–6.8 °C | Davis et al. 20211 |
| Stenophylla, caffeine (dry matter basis) | 0.9–1.9% (Sierra Leone) · 2.05–2.64% (Ivory Coast) | Davis et al. 20211 |
| Stenophylla, SCA consensus score (one sample) | 80.25 | Davis et al. 20211 |
| Judges calling stenophylla arabica | 81% of 15 | Davis et al. 20211 |
| C. zanguebariae, flowering to harvest | ≈4 months (arabica 6–8 months) | Davis et al. 20213 |
| Species assessed · threatened (2019) | 124 · 75 (13 CR, 40 EN, 22 VU) | Davis et al. 20194 |
| Species in no germplasm collection (2019) | 45% | Davis et al. 20194 |
| Red List category (version 2026-1) | Stenophylla VU · C. zanguebariae VU · C. racemosa NT · C. affinis DD | IUCN5 |
Open questions#
- Stenophylla on farms. The flavour and climate data come from a few samples and from wild occurrence records; yields, disease response and cup quality across sites are not established.1,2
- What collections really hold. Mislabelled accessions and open pollination mean that genebank holdings of rare species need genotyping.2,4
- Long-term storage. Coffee seeds tolerate only partial drying, so safe back-up of field collections depends on methods such as cryopreservation.6,10
Key studies#
Davis et al., 2021 – Arabica-like flavour in a heat-tolerant wild coffee. Compares the climate of wild stenophylla with that of arabica, robusta and liberica, and runs sensory panels. Finds an arabica-like flavour profile in a species that grows 6.2–6.8 °C warmer than arabica.
Davis et al., 2020 – Stenophylla and C. affinis rediscovered. Combines old literature, herbarium records, fieldwork in Sierra Leone and DNA sequencing. Rediscovers both species in the wild, rejects a hybrid origin for C. affinis and shows that crosses are possible across the main African species groups.
Davis et al., 2021 – Hot coffee from East Africa. Confirms C. racemosa and C. zanguebariae as distinct species and profiles their climate, agronomy and flavour. Identifies heat tolerance, low rainfall need and a short fruiting cycle as traits for breeding.
Davis et al., 2019 – Extinction risk of all coffee species. Applies the IUCN Red List criteria to the 124 species then known and checks which are held in collections or protected areas. Finds at least 60% threatened and sets priorities among crop wild relatives.
- Recalcitrant or intermediate seeds: the 2019 extinction-risk study calls coffee seeds recalcitrant, “not storable using conventional methods”4; seed physiologists class all *Coffea* species as intermediate, seeds that tolerate partial but not complete drying.6 Both agree that conventional seed banking does not work.
- One species or two: a 2020 DNA study places *C. affinis* as sister to *C. stenophylla* and finds them “possibly a single species”, while both names remain accepted.2
Coffearium (2026). Stenophylla and other wild relatives. Coffearium – The open coffee compendium. Retrieved 22 October 2026, from https://coffearium.org/entries/stenophylla-and-wild-relatives/
@misc{coffearium2026-stenophylla-and-wild-relatives,
author = {{Coffearium}},
title = {{Stenophylla and other wild relatives}},
year = {2026},
howpublished = {Coffearium -- The open coffee compendium},
url = {https://coffearium.org/entries/stenophylla-and-wild-relatives/},
urldate = {2026-10-22},
note = {Retrieved 22 October 2026}
}Entries are updated when the evidence changes; the retrieval date tells your readers which version you used. Changes are listed in the Change log.
Change log
- – Native range of C. racemosa extended to eastern Zimbabwe and KwaZulu-Natal (South Africa), also in quick facts. Reason: The 2021 Frontiers study gives central and southern Mozambique, eastern Zimbabwe and northern South Africa.
- – Crop wild relative priority groups now cited to the 2019 Science Advances study instead of the 2020 Frontiers study. Reason: The priority group system is defined in the 2019 study.
- – Softened three statements: Sierra Leone accessions 'appear to be' hybrids; 'some' (not 'many') institutions apply Nagoya rules to pre-1992 material; small seeds and low yields limited stenophylla in Uganda. Reason: The sources say 'suggest that they represent', 'some institutions' and refer to Uganda.
Sources
- ADavis, A. P.; Mieulet, D.; Moat, J.; Sarmu, D.; Haggar, J. (2021). Arabica-like flavour in a heat-tolerant wild coffee species. Nature Plants 7(4), 413–418. doi:10.1038/s41477-021-00891-4 · other copies
- ADavis, A. P.; Gargiulo, R.; Fay, M. F.; Sarmu, D.; Haggar, J. (2020). Lost and Found: Coffea stenophylla and C. affinis, the Forgotten Coffee Crop Species of West Africa. Frontiers in Plant Science 11, 616. doi:10.3389/fpls.2020.00616 · other copies
- ADavis, A. P.; Gargiulo, R.; Almeida, I. N. das M.; Caravela, M. I.; Denison, C.; Moat, J. (2021). Hot Coffee: The Identity, Climate Profiles, Agronomy, and Beverage Characteristics of Coffea racemosa and C. zanguebariae. Frontiers in Sustainable Food Systems 5, 740137. doi:10.3389/fsufs.2021.740137 · other copies
- ADavis, A. P.; Chadburn, H.; Moat, J.; O’Sullivan, R.; Hargreaves, S.; Nic Lughadha, E. (2019). High extinction risk for wild coffee species and implications for coffee sector sustainability. Science Advances 5(1), eaav3473. doi:10.1126/sciadv.aav3473 · other copies
- AIUCN (2026). The IUCN Red List of Threatened Species, version 2026-1 (via GBIF.org). International Union for Conservation of Nature; GBIF, licence CC BY 4.0. doi:10.15468/0qnb58 · other copies
- AStavrinides, A. K.; Dussert, S.; Combes, M.-C.; Fock-Bastide, I.; Severac, D.; Minier, J.; Bastos-Siqueira, A.; Demolombe, V.; Hem, S.; Lashermes, P.; Joët, T. (2020). Seed comparative genomics in three coffee species identify desiccation tolerance mechanisms in intermediate seeds. Journal of Experimental Botany 71(4), 1418–1433. doi:10.1093/jxb/erz508 · other copies
- ALachenmeier, D. W.; Montagnon, C. (2024). Convention on Biological Diversity (CBD) and the Nagoya Protocol: implications and compliance strategies for the global coffee community. Foods 13(2), 254. doi:10.3390/foods13020254 · other copies
- ASalojärvi, J.; Rambani, A.; Yu, Z.; Guyot, R.; et al. (2024). The genome and population genomics of allopolyploid Coffea arabica reveal the diversification history of modern coffee cultivars. Nature Genetics 56(4), 721–731. doi:10.1038/s41588-024-01695-w · other copies
- BHerrera, J. C.; Lambot, C. (2017). The Coffee Tree – Genetic Diversity and Origin. In: Folmer, B. (ed.), The Craft and Science of Coffee, Academic Press, ch. 1, pp. 1–16. doi:10.1016/B978-0-12-803520-7.00001-3 · other copies
- BCrop Trust (summary of Bramel, P.; Krishnan, S.; Horna, D.; Lainoff, B.; Montagnon, C., 2017) (2017). Global conservation strategy for coffee genetic resources: summary for ITPGRFA stakeholders. Crop Trust.
- AChabrillange, N.; Dussert, S.; Engelmann, F.; Doulbeau, S.; Hamon, S. (2000). Desiccation tolerance in relation to soluble sugar contents in seeds of ten coffee (Coffea L.) species. Seed Science Research 10(3), 393–396. doi:10.1017/S0960258500000428 · other copies
Tier A · authoritative · B · trade and expert · C · general. Supporting quotes for every source are in the data version of this entry. If a publisher’s site refuses access, try the doi link or “other copies”.
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