Lithops 'Optica Rubra'
Lithops 'Optica Rubra is the celebrated purple-red form of Lithops optica, a living stone selected for its striking violet, ruby and burgundy body colour. Where the ordinary species is greyish and easy to overlook, 'Optica Rubra' glows in shades of wine and lilac, making it one of the most recognizable and sought-after cultivars in the whole genus.
Care follows the parent species, Lithops optica — see that page for full detail.
Description
Like all Lithops, 'Optica Rubra' consists of a pair of fused, swollen leaves forming a small cleft body, or "head", that sits mostly buried in the wild with only its flattened top exposed. The distinguishing feature of optica is that the two lobes are drawn up into fingerlike, rounded points that curl slightly inward around a deep central fissure, giving the plant a soft, distinctly two-lobed look rather than the flat-topped window of most species.
In 'Optica Rubra' the entire body carries the purple-red pigment — the lobes, the flanks and the translucent windowed top all take on tones from soft mauve to deep ruby, intensifying under strong light and cooler temperatures. White daisy-like flowers with a pale centre emerge from the fissure in autumn, opening in the afternoon over several days. The colour is heritable but variable, so seed-grown batches range from richly coloured plants to duller, greener throwbacks; the best forms are those selected for the deepest, most even pigment.
Cultivation
Cultivation is as for the parent species, Lithops optica, and the general Lithops regime: a very gritty, fast-draining, almost entirely mineral mix, a deep pot to accommodate the long taproot, and the strict seasonal watering rhythm that living stones demand. Water in late summer and autumn to fuel flowering, taper off through winter, and keep the plant completely dry during the spring leaf change while the old leaf pair is reabsorbed and a new one forms — watering during this "leaf change" is the classic way to lose a plant.
Give 'Optica Rubra' as much bright light as you can manage short of scorching. Good light is not optional here: the red pigment fades toward dull green in shade, and strong illumination is what keeps the celebrated colour saturated. Because optica hails from a narrow coastal strip of Namibia with mild, foggy conditions, it tolerates a little less baking heat than some desert species, but it still wants airflow, brightness and a bone-dry rest. See Repotting for handling the deep root system.
Propagation
'Optica Rubra' is raised almost entirely from seed, sown onto a mineral surface kept warm and humid; select the reddest seedlings to maintain the colour. Mature clumping heads can occasionally be divided, but division is slow and risky compared with seed. See Propagation - seed for the full method.
See also
- Lithops — the genus overview
- Soil and potting mix · Watering · Propagation - seed · Repotting