Lophocereus
Lophocereus is a small genus of columnar cacti native to the Sonoran Desert of northwestern Mexico and the far southwestern United States. Its members are slender, many-branched shrubs and small trees, and the genus is best known for the senita (Lophocereus schottii), whose bizarre monstrose mutant — the beloved totem-pole cactus — is one of the most recognisable oddities in cultivation. Some taxonomists sink Lophocereus into the larger genus Pachycereus, and you will often see the plants listed under both names.
Description
Lophocereus are ribbed, columnar cacti that branch mostly from the base to form open, candelabra-like clumps of upright grey-green stems. The stems are relatively slender for a columnar cactus and firm-fleshed, carrying a modest number of prominent ribs lined with areoles.
The genus's defining feature is the way flowering stems change character near their tips. As a stem matures it develops a "pseudocephalium" — a zone of long, bristly, hair-like spines crowded around the upper areoles, quite different from the short, stouter spines lower down. The small nocturnal flowers, pink to pale, open at night among these bristles and are followed by small fleshy fruit. In the wild the senita's flowers depend heavily on a specialised moth for pollination, one of the classic examples of a plant and its pollinator relying on one another.
Distribution
The genus is centred on the Sonoran Desert, spanning the Mexican states of Sonora and much of the Baja California peninsula, and reaching just into southern Arizona in the United States. Plants grow in hot, arid desert scrub, often on sandy or rocky flats among other columnar cacti, mesquite and creosote bush.
Notable species
- Lophocereus schottii — the senita, by far the most widely grown; a clumping, bristle-tipped column and the source of the famous totem-pole form.
- Lophocereus gatesii — a lesser-known Baja California species, treated by some authors as a variety or synonym of the senita.
Because the boundaries of Lophocereus are still debated, the exact species count varies from author to author; several names once placed here are now folded into L. schottii or moved to Pachycereus.
Cultivation
Senita and its relatives are undemanding for anyone who can grow other desert columnar cacti. Give them the brightest position you have, a very free-draining, mostly mineral mix, and generous warmth. Water thoroughly through the growing season once the soil has dried, then taper off and keep the plants dry and cool through winter; they are far more tolerant of drought than of soggy roots. Protect from hard frost — a light, brief chill is usually shrugged off, but prolonged freezing causes scarring or rot. See Watering and Repotting for general technique.
Hobby and cultivar notes
The plant that draws most collectors to the genus is the totem-pole cactus, a monstrose (irregular, knobbly) mutant of L. schottii. It is nearly spineless, with a smooth, lumpy, sculptural body that looks hand-modelled — hence the name. Being a mutation, it does not come true from seed and is propagated vegetatively from cuttings or, for speed and vigour, by grafting onto a sturdier rootstock.
Ordinary senita is easy from seed and, like most clumping columnars, from stem cuttings once a length of stem has callused. See the Propagation — seed and Propagation — cuttings guides for details.
See also
- Pachycereus — the genus into which Lophocereus is sometimes merged
- Lophocereus schottii — the senita and totem-pole cactus
- Grafting · Soil and potting mix · Watering · Propagation — cuttings