Coryphantha tripugionacantha

Coryphantha tripugionacantha A.B.Lau is the three-dagger pincushion of far western Zacatecas, described in 1988 by Alfred Bernhard Lau in volume 33 of Cactaceas y Suculentas Mexicanas. The epithet is built from Greek tri (three), Latin pugio (dagger), and Greek acantha (spine): three projecting dagger-like central spines per areole, black on fresh growth, stout-based and flattened in cross-section. That geometry is the entire reason for the name, and it remains the single most useful field mark on a mature plant.

The protologue rests on material Lau collected from the canyon country of Mezquital del Oro municipio in 1983, distributed under field number L 1517. The type locality, San Juan Capistrano at approximately 1000 m, is the most-cited site. A second cluster of records at Puente Tepetatita on the Jalisco side of the same drainage system extended the known range across the state line in the early 2000s. Kew POWO and GBIF both accept the Zacatecas and Jalisco occurrence; older popular literature lists Zacatecas only.

Within the genus, C. tripugionacantha sits in series Pycnacanthae alongside heavily spined relatives. The most visually similar species in cultivation are Coryphantha werdermannii, the CITES Appendix I endemic of Cuatrociénegas with chalk-white spines, and Coryphantha elephantidens, the volcanic-slope giant of Michoacán with elephant-tusk tubercles and large pink flowers. Both differ from tripugionacantha in spine architecture, body size, and habitat; the three-dagger centrals of tripugionacantha set it apart within the genus at a glance.

Among serious collectors, the species carries added cachet from its Lau provenance. Plants traceable to documented L 1517 lineage or to the Tepetatita records command a premium in the specialist seed trade simply because accurate locality data is scarce and the population is not large. Vague provenance claims should be treated with scepticism; any plant offered as C. tripugionacantha outside Zacatecas-Jalisco material should be viewed as suspect.

Taxonomy & nomenclature

The accepted name is Coryphantha tripugionacantha A.B.Lau, published in Cactaceas y Suculentas Mexicanas 33(1): 21 (1988). The protologue describes plants collected by Lau from San Juan Capistrano in the Mezquital del Oro municipio of Zacatecas during 1983 fieldwork, distributed as L 1517. Kew POWO and IPNI both accept the species at full rank under Lau’s 1988 publication; IPNI identifier is 936092-1, GBIF backbone ID is 3954766. No synonyms are in current use.

Family placement is Cactaceae, subfamily Cactoideae, tribe Cacteae. Within Coryphantha, the species sits in series Pycnacanthae as treated by Dicht & Lüthy (2005), alongside heavily spined relatives including C. pycnacantha from Puebla and C. pulleineana from Tamaulipas and San Luis Potosí. The diagnostic adaxial groove running from the spine-bearing areole to the flower-bearing axil on mature tubercles separates the genus cleanly from Mammillaria, where the groove is absent or rudimentary. Molecular phylogenetic work by Vázquez-Sánchez et al. (2022) confirms the Coryphantha placement and the relationships within Cacteae.

No infraspecific taxa and no synonyms are listed by POWO, IPNI, or the CITES Checklist. Older classifications occasionally placed densely-spined Coryphanthas loosely within Lepidocoryphantha or treated them as Mammillaria-allied forms, but tripugionacantha was described after those rearrangements and has only ever appeared at species rank within Coryphantha. No vernacular name is formally established; “three-dagger coryphantha” is descriptive, and “tres puñales” circulates informally in the Spanish-language trade.

Habitat

Coryphantha tripugionacantha occupies a narrow band of arid canyon and mesa habitat in far western Zacatecas, with a small extension into adjacent eastern Jalisco where the Tepetatita drainage cuts the state line. The named localities are San Juan Capistrano in the Mezquital del Oro municipio of Zacatecas (the type site, ca. 1000 m) and Puente Tepetatita in Jalisco, the post-2000 discovery that extended the known range across the watershed. Beyond those two clusters of records, published locality data is sparse.

The terrain is broken volcanic mesa and canyon wall where the Sierra Madre Occidental drops east toward the Mezquital basin. Elevation across the known range runs from approximately 1000 to 1100 m. The primary substrate is volcanic-derived, low-organic soil; the thin rocky profiles typical of exposed canyon rims drain quickly and support the xeric shrub communities this species grows within. Climate is the northern Mexican summer monsoon pattern: summer rain arrives July through September and triggers the main growth flush; winter is cold and dry.

iNaturalist carries only a handful of public observations for the taxon, and field-number databases hold the Lau records without sharp GPS coordinates. The vagueness is partly deliberate. Populations are small and the species has visible appeal to poachers given the striking spine arrangement. The working assumption among growers is that the bulk of the wild population sits within roughly 30 km of San Juan Capistrano. Any record outside Zacatecas-Jalisco material should be treated with scepticism.

Morphology

Bodies are solitary, depressed-globose to short-cylindric, dark grey-green, reaching approximately 9 cm in diameter and 7 to 9 cm tall at maturity. The plant stays single-headed through life; offsetting is rare and usually a sign of apex damage rather than natural clustering. Tubercles are conical, prominent, arranged in eight and thirteen spirals, with the diagnostic adaxial groove running from the spine-bearing areole at the tip to the flower-bearing axil at the base on mature flowering tubercles.

The spine cluster is the defining feature of the species and the basis for its name. Each areole carries roughly twelve to sixteen pale, slender radial spines arranged in a regular flat pectinate ring against the body, and three (occasionally four) heavy central spines projecting outward. The lower central is the longest, 25 to 40 mm, curving downward and slightly inward. The two upper centrals diverge to either side at a shallower angle and run 18 to 30 mm. All three centrals are stout-based, sharp, and dagger-flat in cross-section rather than round; they emerge jet black with chestnut tips and fade with age to dark tan, then grey on old areoles low on the body. The apical fresh spines hold close to black through the first growing season after they harden. Among Coryphanthas, this combination of three flattened dagger-centrals on a small, otherwise compact body is unique and constitutes the field mark.

Flowers open at the apex from August through mid-October, occasionally into the first week of November in cultivation. Single blooms, sometimes paired, 6 to 7 cm across, pale lemon yellow. Outer tepals carry a faint red midstripe that flushes pink by the second day of opening. Stamens are yellow; stigma lobes pale green to yellow-green. Fruit is small, fleshy, light green, drying as the seeds mature and releasing through the base. Seeds are pale brown and reticulate-pitted, consistent with the genus pattern.

Locality detail

The type locality is San Juan Capistrano in the Mezquital del Oro municipio of Zacatecas, at approximately 1000 m elevation. The protologue published by Lau in 1988 cites this location, and it remains the most-cited site in the subsequent literature. Herbarium and collector data are consistently vague at the sub-municipio level; sharp GPS coordinates do not appear in publicly accessible databases, and this is deliberate. The populations are small, the terrain is remote, and the striking spine arrangement makes the species visible from a distance to anyone who knows what to look for.

The Tepetatita locality in eastern Jalisco was established by post-2000 collections and extended the known range across the state line where the Tepetatita drainage cuts westward from the Zacatecas escarpment. POWO and GBIF both carry the Jalisco occurrence. The two site clusters are separated by roughly 20 to 30 km of rugged terrain; whether the populations are continuously distributed across that gap or truly disjunct has not been resolved in the published literature. The map above marks approximate centroids rather than precise GPS points.

Cultivation

Coryphantha tripugionacantha is an intermediate-level cultivation subject. It tolerates the mineral-dominant substrates appropriate to northern Mexican canyon cacti, flowers reliably when winter dormancy is respected, and shows no particular sensitivity to humidity beyond the standard Mexican Highland requirement for sharp drainage. The two failure modes that account for almost all losses are root rot from winter watering and failure to flower the following season after a warm wet winter. Both are avoided by respecting the cool dry November-to-March rest.

Substrate

The correct mix is 35% pumice, 20% lava, 10% zeolite, 20% granite grit, 5% crushed limestone, and 10% worm castings. The habitat substrate is volcanic-derived (Mezquital del Oro volcanic terrain), but the slight limestone-compatible pH range of 6.8 to 7.2 justifies a small limestone fraction rather than the strongly alkaline recipe used for dedicated Chihuahuan limestone-hill species. No silica addition is called for. Root rot is the species’ most reliable killer in cultivation; any mix that retains moisture more than three to four days after a soak is unsuitable.

Watering and light

Drench thoroughly from late March through early October when the pot is bone dry. Complete dry-down between waterings is required; the canyon habitat this species occupies drains rapidly after monsoon rain, and the root system is calibrated to cycles of saturation and desiccation rather than sustained moisture. Cut watering sharply from mid-October as nights cool. Hold the plant cold and dry through winter; cool dry conditions through winter are essential for flowering the following season.

Light requirements are full sun. Spine colour and spine length both improve with maximum light exposure; the jet-black fresh centrals that define the species’ visual appeal require strong UV to develop and hold their colour. A south-facing position is the indoor minimum; outdoor summer growing in temperate climates produces better results. Light shade only at the highest summer angles in low-latitude greenhouses to prevent apex scorch.

Cold tolerance and propagation

The cold floor in cultivation is approximately 5°C with the plant bone dry. The species was collected at roughly 1000 m elevation by Lau, a range where winter temperatures are cool rather than hard-freezing; it is not in the class of high-altitude Coryphanthas that tolerate sustained frost. Frost-free conditions are preferred. Brief excursions near freezing are tolerated if the substrate is fully dry; ice in the pot is fatal. USDA hardiness zones 9b through 11b cover the safe outdoor range.

Propagation in cultivation is from seed. Germination is rapid, typically within six to ten days at 22 to 28°C on a moist sterile mix. Seedlings are slow but trouble-free; diagnostic spination appears at three to four years and first flower at six to eight years under good conditions. Grafting is unnecessary for vigour and flattens the body habit; serious collectors keep this one seed grown. Lau-provenance seed from documented L 1517 lineage or from the Tepetatita records carries the collector premium that makes documented provenance worth establishing and maintaining across generations of cultivation.

Comparison

The closest visual match in the genus is Coryphantha hintoniorum from Nuevo León, which also carries prominent dark central spines on a small solitary body. The distinction is spine geometry: hintoniorum centrals are hooked at the tip, not dagger-straight, and the lateral centrals do not form the flat-bladed triad that characterises tripugionacantha. Habitat also separates the two; hintoniorum is a limestone-exposure plant from the San Pablo area of Nuevo León, well east of the Sierra Madre Occidental range of tripugionacantha.

Coryphantha pulleineana from Tamaulipas and San Luis Potosí is the second confusable species in the Pycnacanthae series. It also carries three to five long, dark projecting central spines on a small solitary body, but the centrals are round in cross-section rather than flattened, run longer in old plants, and emerge from a different spiral pattern with fewer and coarser radials. Range separates them cleanly: pulleineana is a Sierra Madre Oriental plant and tripugionacantha a Sierra Madre Occidental plant with no range overlap.

Coryphantha ramillosa, the US-listed Threatened bunched cory of Brewster County, Texas and adjacent Coahuila, offers a different comparison: similar small body, similar conservation-priority status, but a clustering habit rather than the solitary form of tripugionacantha, and pink rather than yellow flowers. Legally defensible plants of ramillosa come only from seed-grown stock given the US Threatened listing; the same documentation discipline applies to tripugionacantha under CITES Appendix II.

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