Family: Cactaceae
Habitat: Stenogonia is not present in nature, as it is a nursery-produced chimera.
Cultivation: Cultivation follows the rules common to other cacti: a very draining soil rich in inerts, direct light, little water. The temperature must always remain above 8-10°C.
Curiosity: Stenogonia is a chimera between Stenocereus sp. and Obregonia denegrii, obtained through grafting. A chimera is, in botany, a plant or a plant part that is a mixture of two or more genetically different types of cells.

KEY FEATURES

Stenogonia is an artificial genus produced in nursey through different grafting of Stenocereus on Obregonia denegrii. Depending on the Stenocereus species grafted, we obtain a different species of Stenogonia.

Stenogonia is called, in botany, a chimera. In mythology, a chimera is a fantastic creature made up of parts of different animals. A typical example is the griffin, a legendary monster with the body of a lion and the head of an eagle. In botany, instead, a chimera is a plant or a plant part which is mixture of two or more genetically different types of cells. This means that, in the same organism, we have two different DNAs: in the case of Stenogonia, the DNAs of both Stenocereus and Obregonia denegrii. These two DNAs give thus two different kinds of information to the plant, which usually develops all kinds of oddities and monstruosities: parts of plants of a completely different colours, strange protuberances of irregular or monstrous shape, and many other bizzarre possible shape that depend on the mother plants. Every chimera is unique. This means that two chimeras obtained by using the same species for the grafting may be different. That’s because the response to the combinated information of the two DNAs may be different in each individual.

There are both natural and artificial chimeras. Natural chimeras are produced when a spontaneous genetic mutation occurs. In this case, the mutation expresses itself usually as a color variation. The most frequent case is that the genetic mutation hinders the production of chloroplasts; so that a portion of the stem may loose its colour and appear lighter or even white. An artificial chimera can be instead obtained either through grafting or through exposition to gamma rays. After a grafting, portions of DNAs of the rootstock may move to the scion and the latter may express losses of colour, mottlings or deformities. The exposition to gamma rays, instead, causes the loss of the capacity to produce chloroplasts in the exposed parts and so, if the exposed part is too large, it may be necessary to graft it anyway so that the rootstock can perform the photosynthetic function and thus ensure the survival of the plant.

Let’s come back to our Stenogonia: depending on the species grafted, its aspect may be diverse. However, it is a little cactus, with a dark green stem divided into seven, deep ribs. On the ribs, white, small areoles are lined up and, from each areoles, usually around seven spines develop, each of a different length. The stem is often streaked with whitish or lighter colours and may show, in some cases, odd crested shapes and other kind of irregular, lumpy forms.

VARIETY AND TYPES

Being Stenogonia a nursery-produced chimera, we don’t have a list of species and varieties: the only one is Stenogonia cv. Stenocereus sp. x Obregonia denegrii, which is actually a name that implies that any Stenocereus species may be used to obtain the chimera. Frequently, Stenocereus griseum is used.

TIPS FOR GROWING

Here below are our cultivation tips for growing your Stenogonia:

• It requires plenty of light all year round, avoiding direct sunlight in particularly during the hot hours.
• It is preferable to keep it at mild temperatures and never below 5 °C. It is recommended to shelter it during the winter period.
• Water moderately in Spring and Summer, always waiting for the soil to dry completely before each watering. In Winter, instead, it is advisable to completely stop watering.
• A well-draining and mineral-rich substrate is an optimal solution, for example a standard soil for cactaceae, to which fine gravel can be added.
• They do not need frequent fertilization, it is sufficient to dilute the fertilizer with watering once a year.
• Repotting necessities depend on the species grafted: usually, once a year or two will be sufficient.

Propagation is carried out through grafting.