Coryphantha werdermannii
Coryphantha werdermannii Boed. is a small solitary globose cactus described by Friedrich Bödeker in 1929 in volume 1, page 155 of the Monatsschrift der Deutschen Kakteen-Gesellschaft. Bödeker named the species in honour of Erich Werdermann, the Berlin-Dahlem botanist whose Mexican fieldwork in the late 1920s supplied many of the type specimens that anchored early twentieth-century taxonomy of Mexican Cactaceae. Plants of the World Online accepts the name without qualification and treats Coryphantha densispina Werderm. as a heterotypic synonym.
The species is the only member of its genus currently listed on CITES Appendix I, placing it in stricter international trade regulation than any other Coryphantha. The formal IUCN Red List category is Least Concern, assessed in 2017, but multiple horticultural sources describe the plant as endangered. Those two framings are not contradictory: the Red List reflects current population stability on intact limestone outcrops; the endangered language in trade literature reflects the narrow geographic range and the Appendix I history. This page reports both correctly.
Among the five Coryphantha taxa covered on this site, C. werdermannii is the most tightly restricted by legal regime. Coryphantha elephantidens, the large-tubercled flowering species from Michoacán, and Coryphantha ramillosa of Brewster County, Texas, both require documentation to trade, but neither sits on Appendix I. C. werdermannii alone demands the full export-and-import permit chain that applies to the most strictly protected Cactaceae on the planet.
Visually, the species goes through a transition that no photograph of a juvenile plant prepares you for. Young plants produce only fine, flattened, bone-white radial spines that lie flat against the body, giving the plant a chalky pincushion look. As the plant matures, two to four stout dark central spines erupt from each areole and within a season or two the chalky juvenile silhouette becomes a fierce, projecting adult. Both stages circulate in cultivation under the same name; collectors who have only seen juveniles are often startled by what the plant becomes.
Coryphantha werdermannii quick reference
A limestone-obligate Chihuahuan Desert cactus from central Coahuila, Chihuahua, and Durango, growing on calcareous gravel at 770 to 1,600 m. Values calibrated for seed grown plants in cultivation, drawn from species-specific habitat data and grower consensus for C. werdermannii rather than genus-level extrapolation.
Taxonomy & nomenclature
The accepted name is Coryphantha werdermannii Boed., published in Monatsschrift der Deutschen Kakteen-Gesellschaft 1: 155 in 1929. Friedrich Bödeker described the species directly in Coryphantha; there is no basionym. Kew POWO accepts the name without qualification. POWO also accepts Coryphantha werdermannii subsp. unguispina Halda, Kupčák & Sladk. (2000) as an infraspecific name, though several authorities including Anderson and the New Cactus Lexicon treat the unguispina form as part of the broad morphological range of the species rather than a distinct subspecies.
The principal heterotypic synonym is Coryphantha densispina Werderm., which describes plants from the same Coahuilan limestone country under a name that emphasises their dense spination. Field collections labelled C. werdermannii subsp. unguispina PP 200, collected by Pavel Pavlíček from the Cuatrociénegas-Torreón area, circulate in European hobby trade; under the POWO concept they are taxonomically the same species regardless of label.
The species belongs to Cactaceae subfamily Cactoideae, tribe Cacteae, alongside Mammillaria, Ariocarpus, Astrophytum, and Echinocactus. Within the Cuatrociénegas region it is one of several locally endemic small globose Coryphantha taxa; it can be told apart from nearby C. durangensis and C. poselgeriana by spine count, flower colour, and the juvenile-to-adult spination transition that is the species’ most diagnostic field character.
Historical synonyms (2)
- Coryphantha werdermannii subsp. unguispina Halda, Kupcák & Sladk., 2000 homotypic synonym
- Coryphantha wedermannii Boed., heterotypic synonym
Sources: GBIF
Habitat
POWO records the native range of C. werdermannii across three Mexican states: Coahuila, Chihuahua, and Durango. The functional centre is the Cuatrociénegas basin and the Sierra de la Paila in central Coahuila, where the type material was collected and where modern field collections, including SB 575, ISI 90-5, and PH 517.5/517.6, all anchor the species to the same limestone landscape. Several horticultural sources cite San Luis Potosí and Puebla in addition to Coahuila; those records are inconsistent with the POWO range and most likely reflect confusion with the C. pallida and C. clavata complex, which does reach those southern states. POWO is the project’s taxonomic authority and is followed here.
The substrate is the load-bearing ecological feature. C. werdermannii is an obligate limestone plant. It grows on calcareous gravel and shallow rendzina soils on rocky outcrops and is essentially absent from the gypsum flats and yeso dunes of the Cuatrociénegas valley, which belong to the gypsophile-cactus community occupied by other genera. The associated flora includes Echinocereus conglomeratus, Epithelantha micromeris, Neobuxbaumia macrocephala, and the Chihuahuan Desert matrix shrub Larrea tridentata.
The recorded elevation range across all field collections runs from about 770 m at El Hundido to roughly 1,600 m on the higher slopes north of Parras de la Fuente. Most documented populations sit in the 800–1,200 m band on low limestone hills set in a flat Chihuahuan Desert matrix. The climate is harsh continental: summer maxima above 38°C, winter overnight lows touching −4 to −6°C in clear weather on the higher hills, and total annual rainfall in the 200–300 mm range. Plants in habitat sit fully exposed on south-facing limestone slopes with no canopy shade.
Morphology
Coryphantha werdermannii is a small solitary globose cactus. Mature plants reach 6–9 cm in width and 7–12 cm in height, occasionally elongating to 30 cm in old specimens undisturbed for decades. The body colour beneath the spination is pale grey-green; offsetting is rare.
The tubercles are conical to short-cylindrical, up to 1.5 cm long, with naked axils that lack the wool tufts seen in some Coryphantha species. Each tubercle bears a single areole at the tip. Juveniles produce only fine, flattened, bone-white radial spines, 15–30 per areole, comb-set, lying close to the body, giving the plant a chalky pincushion silhouette. Adult plants then produce two to four stout central spines per areole, dark brown to black, 13–25 mm long, rigid, projecting outward; within a season or two the chalky juvenile look is replaced by a much fiercer adult appearance.
Flowers are produced from the apex of the plant, opening in late spring to early summer in habitat. Each flower is glossy lemon to pale gold yellow, 5–7 cm in diameter and up to 5 cm long, with a deeper pink-suffused throat in some older specimens. The fruits are small green club-shaped bodies about 1 cm long; the seeds are matte black, kidney-shaped, and small. Reproductive maturity from seed takes 8–12 years under good cultivation.
Locality detail
The type locality is the limestone country south of Cuatrociénegas in the Sierra de la Paila system, Coahuila. Bödeker’s 1929 protologue cites material received via the Werdermann collection; the classical type-area aligns with multiple modern field collections from the same landscape.
Steven Brack’s SB 575 and the International Succulent Introductions accession ISI 90-5, both from the immediate Cuatrociénegas area, are the most-traded provenance lines in the European and US hobby and serve as the collector benchmark for what the wild type looks like. Paul Hoxey’s PH 517.5 and 517.6 and Pavel Pavlíček’s PP 200 from the El Hundido hills, approximately 870 m elevation, are the next best-documented locality cluster and are frequently listed in specialist nursery catalogues when the collector number is documented.
The map above marks approximate centroids only. Sharp GPS coordinates for CITES Appendix I cactus populations on accessible limestone hills are deliberately withheld on this page; the localities are published to the resolution already present in the BCSS Field Number Finder and specialist horticultural literature. Anyone proposing to visit these sites for any purpose requires Mexican SEMARNAT permits in advance.
Cultivation
Before any cultivation discussion: legitimate plants come only from a registered nursery whose stock is artificially propagated from seed and accompanied by the full chain of CITES Appendix I documentation. An import permit issued by the destination country and a corresponding export permit from the country of origin are both required. This applies to seedlings, mature plants, and seed lots. Crossing an international border with a C. werdermannii without the correct permits is a CITES infringement regardless of how the plant was acquired.
Substrate
C. werdermannii is a limestone obligate, and its substrate must reflect that. The working recipe is 90 percent inorganic to 10 percent organic, weighted toward calcareous components: 35% pumice (3–6 mm), 10% lava rock (3–6 mm), 20% zeolite, 25% crushed limestone or dolomite (3–6 mm), and 10% worm castings. Target pH is 7.5–8.5. The limestone fraction is what differentiates this mix from a default Coryphantha substrate; without it, plants slowly etiolate and fail to develop the dense spination that defines the species.
The five Coryphantha species on this site split clearly by geology: limestone-hill species carry 15–25% limestone; C. elephantidens is the outlier with zero limestone and a volcanic-derived recipe.
| Species | Pumice | Lava | Zeolite | Granite | Limestone | Silica | Organic |
|---|---|---|---|---|---|---|---|
| C. werdermannii (this page) | 35% | 10% | 20% | 0% | 25% | 0% | 10% |
| C. elephantidens | 30% | 30% | 10% | 20% | 0% | 0% | 10% |
| C. hintoniorum | 35% | 15% | 10% | 15% | 15% | 0% | 10% |
| C. ramillosa | 30% | 20% | 10% | 15% | 15% | 0% | 10% |
| C. tripugionacantha | 35% | 20% | 10% | 20% | 5% | 0% | 10% |
Watering and light
Cease scheduled watering from November through February. The substrate must be bone dry at the pot base through this period. Winter moisture combined with cool temperatures causes rapid root collapse and is the most common cultivation failure mode across every grower source consulted. First spring watering should wait for visible body swelling, typically March or April: a single thorough soak followed by complete drying over 10–14 days. From late spring through early autumn, water when the top 3–5 cm of substrate is fully dry, generally every 10–14 days at temperate latitudes.
Light requirements are full sun, 6–8 hours of direct daily exposure. The chalky white juvenile spination functions as passive solar cooling; plants grown in insufficient light lose the tight body form and fail to develop the characteristic spination. A cool, dry, bright winter rest of three months at 5–10°C night minima is what reliably triggers spring flowering. Ventilation is essential; standing humid air around the plants is a far greater rot risk than any specific temperature minimum.
Cold tolerance and propagation
Cold tolerance, given a dry root run, extends to roughly −4 to −5°C briefly. Treat 0°C as the operating winter floor and keep the substrate bone dry below 5°C. Propagation is from seed only in practice; vegetative offsetting is too rare to be a practical multiplication method. Seed germinates readily on a fine calcareous mix at 22–26°C with high humidity for the first six weeks, after which seedlings move to the standard adult substrate at one year. Grafting accelerates the timeline to flowering but alters the body proportions and prevents the juvenile-to-adult spination transition that defines the species.
Comparison
Within the genus, C. werdermannii is most often confused with Coryphantha hintoniorum, the compact Nuevo León endemic with hooked central spines and pale yellow flowers. The diagnostic check is the central spine shape: C. hintoniorum produces hooked or at least curved centrals, while C. werdermannii centrals are straight and projecting. The flowers of both are in the yellow range but C. werdermannii runs glossier and more intensely lemon-toned. C. hintoniorum is also Nuevo León endemic; C. werdermannii is the Coahuila-anchored species.
C. werdermannii shares the Cuatrociénegas limestone country with C. durangensis and C. poselgeriana. Coryphantha tripugionacantha, Alfred Lau’s Zacatecas discovery with three dagger-like central spines per areole, shares neither the limestone substrate nor the Cuatrociénegas range; it is a southern Chihuahuan species. The three dagger-shaped projecting centrals of C. tripugionacantha are visible at a glance and eliminate any field-confusion risk with the C. werdermannii adult, which has at most four but typically two centrals of a quite different character.
Outside the genus, the chalky juvenile phase of C. werdermannii is sometimes mistaken for a small Mammillaria or an immature Echinocactus horizonthalonius, both sympatric in the Cuatrociénegas region. The diagnostic check is tubercle structure: Coryphantha tubercles bear a furrow on the upper surface running from the spine-bearing apex to the axil, which Mammillaria does not have. Adult C. werdermannii with projecting dark centrals is unmistakable in the field.
Frequently asked questions
Is Coryphantha werdermannii hard to grow?
Advanced. The species demands a limestone-supplemented substrate at pH 7.5–8.5, a completely dry winter rest from November through February, and full-sun exposure to develop its characteristic spination. None of these is especially difficult in isolation, but getting all three right simultaneously, and sourcing legitimate Appendix I documented plants in the first place, raises the bar well above a standard cactus collection. Growers who already keep Chihuahuan Desert cacti on limestone-based substrates find the care profile familiar; those starting from a generic peat-amended compost background will need to rebuild their approach from the substrate up.
Can Coryphantha werdermannii be grown from seed?
Yes, and for most collectors seed is the only legal route to a legitimate plant. Seed germinates at 22–26°C on a moist fine calcareous mix, typically within two to three weeks under good conditions. Seedlings grow slowly; first flower takes 8–12 years from germination under good cultivation. Grafting onto Trichocereus or Harrisia rootstocks accelerates flowering to two or three years, but grafted plants develop a more globose, fatter body than the natural seed grown form and do not go through the same juvenile-to-adult spination transition. Seed from documented provenance with full Appendix I export papers appears in specialist German and Czech seed lists; the seed de minimis exemption under CITES is jurisdiction-specific and should be confirmed before any cross-border purchase.
Is Coryphantha werdermannii legal to own?
Coryphantha werdermannii is currently listed on CITES Appendix I, the strictest international trade category and the only one in the genus. Any international movement of a plant or seed lot for commercial purposes requires both an export permit from the country of origin and a corresponding import permit from the destination country; the scientific authorities of both countries must confirm the trade poses no detriment to wild populations. Wild-collected plants cannot lawfully obtain those permits. Even gifting a single plant across a border without the Appendix I paperwork is a CITES violation regardless of the plant’s value. Within Mexico, the species is additionally listed under NOM-059-SEMARNAT-2010 and regulated through SEMARNAT and PROFEPA permitting. Personal possession of nursery-propagated stock with documented seed-grown provenance is legal in most jurisdictions; the documentation requirement is non-negotiable for any cross-border movement. Any reputable specialist nursery will supply the full paperwork without being asked.
Where does Coryphantha werdermannii grow in the wild?
The core range is the Cuatrociénegas basin and the Sierra de la Paila limestone hills in central Coahuila, Mexico, with outlying populations on equivalent limestone substrates in Chihuahua and Durango per the Plants of the World Online distribution record. Documented field collections are concentrated between 770 m at El Hundido and roughly 1,600 m north of Parras de la Fuente. The species is an obligate of calcareous gravel and shallow rendzina soils on exposed limestone outcrops; it is essentially absent from the gypsum flats and sandy desert areas that surround the limestone hills. Several horticultural sources additionally cite San Luis Potosí and Puebla; those records likely reflect confusion with the C. pallida complex and are not followed here.
When does Coryphantha werdermannii flower?
Late spring through early summer in habitat, broadly May through July, with the peak depending on elevation and year-to-year rainfall timing. Under glass at temperate European and North American latitudes, flowering often runs somewhat later, typically June through August. Each flower is glossy lemon to pale gold yellow, 5–7 cm in diameter and up to 5 cm long; older plants sometimes develop a deeper pink-suffused throat. Flowers open at the apex of the stem, persist two to four days each, and a well-established plant produces several flowers per season. A cool, dry, bright winter rest of three months at 5–10°C night minima is the most reliable trigger for the following spring flowering season.
Sources & further reading
Bödeker, F. (1929). Coryphantha werdermannii sp. nov. Monatsschrift der Deutschen Kakteen-Gesellschaft 1: 155 · Kew POWO. Coryphantha werdermannii Boed. (accepted name, distribution, synonyms). powo.science.kew.org · GBIF. Coryphantha werdermannii occurrence dataset. gbif.org · IUCN Red List. Coryphantha werdermannii assessment 2017 (Least Concern), dataset 2022-2. iucnredlist.org/species/152483 · CITES. Coryphantha werdermannii Appendix I listing; taxon term 8326. cites.org (Species+ taxon ID 19242) · NOM-059-SEMARNAT-2010 and 2019 modification. Diario Oficial de la Federación · Martorell, C., Garcíllán, P.P., Casillas, M., et al. (2014). Assessing the importance of multiple threats to an endangered globose cactus in Mexico: Cattle grazing, looting and climate change. Biological Conservation 170: 179–185 · Hernández, H.M. & Gómez-Hinostrosa, C. (2011). Mapping the Cacti of Mexico, Part I. DH Books · Anderson, E.F. (2001). The Cactus Family. Timber Press. ISBN 0-88192-498-9 · Hunt, D., Taylor, N. & Charles, G. (eds, 2006). The New Cactus Lexicon. DH Books · Dicht, R.F. & Lüthy, A.D. (2005). Coryphantha: Cacti of Mexico and Southern USA. Springer · BCSS Field Number Finder. SB 575, ISI 90-5, PH 517.5/517.6, PP 200; locality and elevation data. bcss.org.uk