Commemorating Charles Lemaire, 1801-71, a famous French cactus specialist (Cactaceae). A genus of some 23 species of greenhouse succulent plants, mostly from South America, with generally erect stems, and large areoles with strong spines. They are day flowering, therather large, with short petals. This is a very good genus for increasing the height of a cactus collection. All the species described below are from Mexico.
L. chende, deep green branches from the base, small white flowers with pale pink midrib. L. chichipe, small plant, reddish spines, white bloom on stem, small flowers, brown-red, and greenish-yellow on inside. L. dumortieri, very prominent ribs, 5-6 funnel-shaped flowers, brownish-white, and reddish outside. L. hollianos, much branched from the base, slender spines, white flowers. L. marginatus, often used forpurposes in Mexico, grey-brown areoles, almost continuous down the edges of the ribs, handsome, bell-shaped, red and greenish-white flowers. L. pruinosus, stem blue when young, flowers funnel-shaped, brownish-green to white.
An average potting compost with 1/2 part extra of sand, grit and broken brick to add to the porosity is the best for these plants; repotting is done every three years, or sooner if pot-bound. Place in a really sunny position in the greenhouse—on tall plants flowering will only take place in full sun. They should be watered between March and September, and kept quite dry for the rest of the year.
Propagate by seed sown in John Innes seed compost, just covered, and kept at a temperature of 70-80 °F (21-27°C), moist, and shaded for the first year. Seedlings are fairly quick growing. Propagate also from side-shoots removed and used as cuttings; when these are dry they soon root in sand.