Encephalocarpus
Encephalocarpus is a formerly monotypic cactus genus erected for the curious, pinecone-like Encephalocarpus strobiliformis of the Chihuahuan Desert of north-eastern Mexico. Modern taxonomy has since folded it into the genus Pelecyphora, so the name is now treated as a synonym — but it is still widely used by collectors, and the plant it describes remains one of the most distinctive of the small Mexican "pebble" cacti.
Description
The single species long placed here, Encephalocarpus strobiliformis, is a small, solitary, mostly geophytic cactus with a stout taproot and a low, rounded body that sits close to the ground. Its most striking feature is its tubercles: broad, flattened, overlapping scales arranged in neat spirals, so the whole plant resembles a small green pine cone or an artichoke — the source of the epithet strobiliformis ("cone-shaped"). The tubercles are keeled and pressed tightly together, and their areoles carry a little wool and, on young tubercles, a few weak, whitish, comb-like spines that soon drop away — so mature plants appear essentially spineless, with a smooth, sculptural surface.
Flowers appear from the growing point near the crown, opening in the warmer months. They are relatively large for the size of the plant, funnel-shaped and a bright magenta to violet-pink, contrasting vividly with the grey-green body. As with related dwarf cacti, the plant tends to draw down into the soil in drought, so that in habitat little more than the flat top of the cone is visible among rock and grit.
Distribution
The species is native to north-eastern Mexico, where it is more widely distributed than its rarity in cultivation might suggest — occurring across parts of Nuevo León, Tamaulipas and San Luis Potosí in the Chihuahuan Desert, generally below about 1,600 m, on rocky, calcareous ground among grass and low scrub. The IUCN currently assesses it as Least Concern, but wild populations have been reduced by illegal collecting, and — like the whole cactus family — it is protected under CITES. It in fact carries the strictest protection: Pelecyphora is listed on CITES Appendix I, which bans international commercial trade in wild-collected plants. Nursery-propagated plants are the only appropriate source for collectors; wild collecting is neither necessary nor legal.
Taxonomy
Encephalocarpus was described as a genus of its own to accommodate the unusual cone-like body of E. strobiliformis. Later study of flower, seed and overall relationships showed it to sit comfortably within Pelecyphora, a small genus of similarly tubercled Mexican cacti, and most current authorities treat Encephalocarpus as a synonym of that genus. Growers may therefore encounter the plant labelled as either Encephalocarpus strobiliformis or Pelecyphora strobiliformis; both refer to the same plant. The genus is monotypic, so this one species is its entire content.
Notable species
- Pelecyphora strobiliformis (syn. Encephalocarpus strobiliformis) — the sole species: the pine-cone cactus, with spiralled overlapping scale-like tubercles and vivid magenta flowers.
For its close relatives, see the Pelecyphora genus page, which now includes this plant alongside the classic "hatchet cactus" species.
Cultivation
Cultivation follows the pattern for small, taprooted Mexican cacti and is best understood through the parent genus Pelecyphora. Grow the plant in a very free-draining, mostly mineral mix with plenty of grit, ideally in a deep pot to accommodate the taproot. Give it bright light to keep the body compact and encourage flowering, and water only when the soil has dried out completely during the growing season.
The taproot makes the plant particularly sensitive to standing moisture, so err firmly on the side of underwatering and keep it dry and cool through winter. Because it is naturally slow and somewhat demanding on its own roots, this species — like many choice Mexican dwarfs — is frequently grafted onto a hardy rootstock to speed growth and reduce the risk of rot. See Watering and Repotting for general technique.
Propagation
The species is normally raised from seed, sown on a warm, humid mineral surface as for other small Mexican cacti (see Propagation — seed). It rarely offsets, so vegetative increase is uncommon apart from grafting, which is also used to bring slow seedlings on more quickly. Named cultivars are not really a feature of this plant; interest lies in the wild form itself.
See also
- Pelecyphora — the genus into which Encephalocarpus is now merged
- Pelecyphora strobiliformis — the single species
- Grafting · Soil and potting mix · Watering · Propagation — seed · Repotting