Gymnocalycium 'LB 2178'
Gymnocalycium 'LB 2178 is a celebrated field-collected line of Gymnocalycium friedrichii (a plant also treated under Gymnocalycium mihanovichii in some references) that has become one of the most sought-after seed parents in the hobby. The name carries a field-collection number — the "LB" series associated with the Dutch Gymnocalycium specialist Ludwig Bercht — and the accession is prized because its seedlings so often throw intensely coloured bodies and vivid variegation, traits that have made it a favourite among Japanese and other Asian collectors.
Because 'LB 2178' is a selected line rather than a distinct species, its care follows that of its parent species, Gymnocalycium friedrichii.
Description
'LB 2178' has the general look of a good friedrichii: a small, somewhat flattened globular body with relatively few broad, sharply angled ribs, a smooth waxy skin and short, weak spines held close to the plant. Depending on the individual, the epidermis ranges from grey-green to deep wine-red, and the whole plant can flush with purple, pink or bronze tones — a colouring that this line passes on strongly to its offspring. Flowers are the pale, satiny pink-white typical of the parent, opening from near the crown.
What sets 'LB 2178' apart is not so much any single plant as its reputation as a seed parent. Batches raised from selected 'LB 2178' stock produce an unusually high proportion of richly coloured, patterned and variegated seedlings, including plants that are wholly or partly lacking green pigment. These fully colour-blocked seedlings are essentially the same phenomenon exploited in the familiar grafted "moon cactus" (see Gymnocalycium), and they must be grafted onto a green rootstock to survive, since they cannot photosynthesise on their own roots.
Cultivation
Grow 'LB 2178' exactly as for the parent species — see Gymnocalycium friedrichii for full detail. In short, it wants a very free-draining, mostly mineral mix, careful watering with a full dry-out between soakings, and a dry winter rest to encourage flowering and prevent rot. Like most Gymnocalycium, it appreciates bright light but is happier with a little shade from the fiercest afternoon sun than the desert cacti, and hard, direct exposure can scorch the softer red-skinned individuals.
Two special notes apply to this line:
- Variegated and colour-blocked seedlings need extra care. Plants low in chlorophyll are weak on their own roots and are almost always grafted; even partly variegated plants tend to grow slowly and sunburn easily, so give them slightly softer light than a fully green plant.
- Selection is everything. The famous colouring is a tendency, not a guarantee — growers rogue out plain green seedlings and breed on from the best-coloured individuals, which is why quality 'LB 2178' seed and stock command a premium.
Routine repotting, pest control and general handling are the same as for any small Gymnocalycium.
See also
- Gymnocalycium friedrichii — the parent species
- Gymnocalycium — the genus overview, including variegated and grafted forms
- Grafting · Soil and potting mix · Watering · Propagation — seed · Repotting