Aztekium ritteri var. rotundum VM 1079

Description

Type: Seed grown · Field number: VM 1079 · Size: about 0.5 in (1.3 cm) across · 5 available, sold individually

Aztekium ritteri rotundum VM 1079 is the carved-stone cactus of the Nuevo León cliffs with one thing our other Aztekium listing lacks: a collector’s field number that ties the line to a recorded wild locality. Five plants of about half an inch are for sale here, sold individually, and the photographs show representative plants from the batch. At rarecactus.com we raise our Aztekium from seed in our Orange County, California greenhouse, and this batch has grown on under the VM 1079 label you can read in the photograph of the potted plant.

What sets Aztekium ritteri rotundum VM 1079 apart

In habitat, Aztekium ritteri clings to near-vertical gypsum and limestone canyon walls, rooted in clay-filled crevices and shaded for most of the day. Its grey-green body is ribbed like a carving: the primary ribs are crossed by fine transverse wrinkles, and a second set of fold-like false ribs runs between them, the detail behind the Aztec name of the genus. The close-up shows a young crown at this stage, a tight star of folded ribs with small tufts of white wool at the areoles.

The name var. rotundum was published in 2019 by Libor Kunte and Jaroslav Šnicer in their monograph on the genus, which appeared in Czech as the first special issue of the journal Kaktusy. Kew does not treat it as a separate taxon: Plants of the World Online lists Aztekium ritteri var. rotundum as a synonym of Aztekium ritteri. Botanically, then, this is Aztekium ritteri. Collectors keep the rotundum name on their labels to follow the line, and so do we. Our Aztekium ritteri specimen page covers the species in depth.

Field data and provenance

VM 1079 is a collector’s field number. A number like this ties a seed line to one wild population at one recorded locality, which is how serious growers keep the natural variation of a species straight across generations in cultivation. Our other Aztekium ritteri listing has no field data; this batch was grown under the number, as the label in the photograph of the potted plant shows. You can browse collector numbers across the genera we grow in our Field Number Database.

The plants themselves are greenhouse raised from seed. Nothing here was taken from the wild.

How we grow it

We grow these in a small, deep pot of about 95 per cent mineral mix with a little limestone, in bright light kept off the harsh midday sun. From spring through summer they get water only once the mix is completely dry, which can take anywhere from ten days to three weeks depending on the heat. Watering tapers in autumn and stops entirely from November to February, with a winter minimum of 5°C. Every plant in the batch is seed grown, with a strong root system, and none has been grafted to push it faster.

Growth runs to about a millimetre a year. A half-inch plant represents years of patience.

Below the surface

The third photograph shows a plant out of its pot. The green crown sits on a firm lower stem that narrows into a slim taproot, and the brown, bark-like skin there is the corking these plants form at the base. That taproot is why the species wants a deep pot rather than a wide one: it grows down, and the tiny root zone should never sit in wet mix.

Flowering

Aztekium ritteri flowers through summer from the woolly crown, with small white to pale pink blooms under a centimetre across. Plants usually need seven to ten years from seed to reach flowering size, so for now the show is the slow sharpening of the wrinkled ribs and a crown that grows a little woollier each year.

When your plant arrives

Your plant ships rooted and dry, in its pot with the surface held in place, inside a box far larger than the plant. When you move it into a pot of your own, choose a small, deep, narrow one and a lean mineral mix with a little limestone, set the plant in bright indirect light, and give no water for about fourteen days while it settles in. After that, follow the dry-between-soaks rhythm above, and keep it completely dry and frost-free through winter, when cold combined with wet roots does the real damage.

Provenance and legality

Aztekium ritteri is listed on CITES Appendix I and protected in Mexico under NOM-059. CITES governs international trade, so a plant shipped within the United States needs no permit, and artificially propagated stock like this batch is the lawful way to own one. We ship to US addresses only. The Aztekium care guide sets out the full year, and the Aztekium encyclopedia hub covers all three species.

Five Aztekium ritteri rotundum VM 1079 plants are offered, each about half an inch across, and you will receive one of comparable size and form.