Pelecyphora
Pelecyphora is a genus of small, slow-growing cacti whose classic species come from the arid highlands of Mexico, best known for the neat, laterally flattened, hatchet- or woodlouse-like tubercles that spiral around the body of those species. The genus name comes from the Greek for "hatchet-bearing," a reference to those distinctive tubercles. Long a small group of just two or three Mexican species, Pelecyphora was substantially enlarged by a 2022 molecular phylogenetic study that subsumed the largely North American genus Escobaria — together with its segregates such as Neobesseya and Cochiseia — into it, pushing the accepted species count to around twenty and extending its range far beyond Mexico. Many growers and some taxonomists still keep these plants under Escobaria, and the change is not universally accepted.
Description
In its traditional, narrow sense, Pelecyphora comprises dwarf, globular to shortly cylindrical cacti, usually solitary but sometimes clustering with age. The defining feature is the tubercles, which in the type species are strongly compressed side-to-side and arranged in dense spirals, each crowned by a narrow, comb-like areole bearing tiny, tightly packed spines pressed flat against the plant. The overall effect is intricate and geometric, and it is what makes these plants so prized among collectors of miniature cacti.
Bodies are typically only a few centimetres across. Flowers appear near the crown, are relatively large for the size of the plant, and range from magenta and violet-pink to pale, near-white tones depending on the species. As with most small Mexican cacti, roots are often thickened or tuberous, an adaptation to storing water and surviving long dry spells.
Under the broad 2022 circumscription the genus also takes in the former Escobaria species — small, tubercled, globular to shortly cylindrical North American cacti, many with ordinary radiating spines rather than the flattened, comb-like clusters of the classic species. This makes the enlarged genus noticeably more variable in form and hardiness, and is one reason the change remains contentious in the hobby.
Distribution
Pelecyphora in the narrow sense is endemic to north-central and northeastern Mexico, chiefly the states of San Luis Potosí, Nuevo León and neighbouring areas of the Chihuahuan Desert region. Plants grow in gritty, mineral-rich soils on limestone hills, flats and gypsum outcrops, often partly buried and easily overlooked among rock and low scrub. Under the broad treatment the range becomes far larger, because the former Escobaria species extend north through the western United States and Great Plains into the Canadian prairies, making the enlarged genus one of the most widespread in the family.
Many of the Mexican species are slow-growing habitat specialists with small, over-collected wild populations: both classic species, P. aselliformis and P. strobiliformis, are listed on the strictest CITES Appendix I, while all cacti are covered at least by Appendix II. Nursery-propagated plants are widely and legally available; wild collection is both damaging and, for these taxa, illegal.
Notable species
- Pelecyphora aselliformis — the type species, the "peyotillo," instantly recognised by its dense spirals of flattened tubercles topped with comb-like spine clusters and magenta flowers.
- Pelecyphora strobiliformis — the pinecone cactus, formerly placed in its own genus Encephalocarpus; overlapping, leaf-like tubercles give it the look of a small green cone or bud.
Under the expanded 2022 treatment the genus also takes in the numerous North American species formerly placed in Escobaria (such as P. vivipara and P. missouriensis), though many collectors continue to catalogue these under the familiar name Escobaria pending wider acceptance.
Cultivation
As a group, Pelecyphora are rewarding but demand the same restraint as most small Chihuahuan-Desert cacti: they are far more often lost to overwatering than to neglect. Grow them in a very free-draining, mostly mineral mix — generous grit or pumice with only a little organic matter — in a snug pot that lets the substrate dry quickly. Bright light brings out the tight spination and compact form; too little light causes soft, etiolated growth.
Water thoroughly only once the soil has dried right through during the growing season, and keep the plants dry and cool through winter to encourage flowering and guard against rot. The thickened roots are prone to rot in stagnant, damp conditions, so airflow and sharp drainage matter more than feeding. See Watering and Repotting for general technique.
Because these species are naturally slow from seed, many growers speed up young plants by grafting seedlings onto a vigorous rootstock, later growing them on their own roots or keeping them grafted for display.
Propagation
Seed is the standard method for the genus; the fine seed germinates on a warm, humid mineral surface and seedlings are grown on carefully for their first years. Species that offset can also be increased vegetatively, and grafting is widely used to accelerate otherwise glacial growth. See Propagation — seed, Propagation — offsets and Grafting.
Hobby and cultivar notes
Pelecyphora plants are collector's items rather than mass-market cacti, valued for their miniature size, geometric tubercles and jewel-toned flowers. Crested and monstrose forms of P. aselliformis occasionally appear and are sought after; as with variegates and crests in general, these unusual forms often grow best grafted and may need slightly brighter, more attentive care than typical plants. The taxonomy remains a live topic among enthusiasts, so plants are frequently sold and discussed under both their traditional and their newer names — worth keeping in mind when buying or swapping.
See also
- Escobaria — genus subsumed into Pelecyphora under the broad 2022 treatment
- Turbinicarpus — closely related genus that absorbed several plants once placed in Pelecyphora
- Grafting · Soil and potting mix · Watering · Repotting · Propagation — seed · Pests and diseases