Publication: Sukkulentenkunde 7/8: 95. 1963
Description
Echinopsis densispina var. pectinifera firstly described as Lobivia pectinifera is an hight altitude form of the wide ranging and very variable Echinopsis densispina with shirt pectinated spines. The differences with other Echinopsis densispina are in reality very minimal and most botanist agree on the fact that both should all be included in the Echinopsis densispina. The segregation of the many forms, varieties, and subspecies on the basis of spines morphology and flowers colour, however, is difficult to support, given the continuous range of variation in spination and flower colour over its geographic range.
Habit: Solitary or forming clusters or cushions from a large tap root, it is a very variable specie with several different forms.
Stem: Ovoid, greyish-green, dull green or brown-purplish-green, up to 8 cm tall and 5 cm in diameter.
Ribs: Approximately 17, more or less notched, forming tubercles.
Areoles: Yellowish-white, somewhat sunken, about 5 mm apart.
Central spines: Usually absent.
Radial spines: 16-22, Short, somewhat pectinated and appressed against the stem, bristle-like, flexible, whitish, 4 mm long. Forming a network that shades the body.
Flowers: The flowers occur in many colours, varying from yellow to orange and red, up to 8,5 cm long.
Origin and Habitat
Tilcara, Jujuy, Argentina
Altitude: 2700 metres above sea level.
Cultivation and Propagation
Echinopsis densispina is a summer-growing species that offers no cultivation difficulty, not as badly affected by moisture as other cactus species. It makes great potted specimens.
Soil: Use a mineral well permeable soil with little organic matter (peat, humus). It grows in limestone areas of Texas (Big Bend area) and adjacent areas of Mexico, so will probably benefit from extra calcium in its soil.
Growth rate: It grows well, though slowly, but it possible to increase the speed of growth to some extent by providing adequate amount of water, warmth, and a liquid fertilizer diluted half strength during the active growing season, but it’s susceptible to rotting if too wet. Most plants will offset readily, and clumps can be produced in a few years.
Soil: It needs a very porous, slightly acidic potting medium (add pumice, vulcanite, and perlite). Outdoors it does well on poor, rocky soils.
Fertilization: Feed with a high potassium fertilizer in summer.
Exposure: It likes a sunny position also blasting sun in summer. If grown indoor provide 4 to 6 hours, or more, direct morning or afternoon sun.
Watering: It should be watered regularly in Summer allowing to dry before watering again and kept drier in Winter. It is very drought-tolerant.
Hardiness: It can be grown outdoors in frost-free climates, needs anyway to kept above 5 °C and dry in winter. But it can tolerate temperatures down to -5° C (or even less) for very short periods if very dry and ventilated. During winter month, put them in a cool luminous place and encourage them to enter winter dormancy by withholding water and fertiliser over the winter as they will etiolate, or become thin, due to lower levels of light.
Maintenance: Repot every two years. Needs lots and lots of space to grow, use large shallow container or bowl filled with very porous compost. It like pots with generous drain holes.
Pest & diseases: They are susceptible to fungal diseases if overwatered, but are not nearly as sensitive as many other cacti, especially in warm weather. If kept damp through cold periods, they will invariably suffer.
Propagation: Seeds or cuttings. The seeds may be germinated and grown in containers. Their main requirements consist of high humidity levels, free-draining soil mix, and enough water, light, and nutrition.