Pianta dalla geometria perfetta con quattro costole simmetriche invece di cinque. Molto bella e caratteristica.

Family: Cactaceae (Cactus Family)

Accepted scientific name:  Astrophytum myriostigma Lemaire "quadricostatum"
Original description: Cactacearum Genera nova Speciesque novae et omnium in Horto Monvillano cultarum: 4-6 1839 

Origin:  Garden origin. Four ribbed plants of Astrophytum myriostigma are occasionally found in a natural habitat, but  the clones actually in cultivation are of garden origin (Nursery produced cultivars).

Conservation status: Listed in CITES appendix 2.

Synonyms:

Etymology: "quadricostatum"  just means it has 4 ribs. There are some other varieties of the 4 ribs, such as "nudum quadricostatum", "variegated quadrocostatum", "Onzuka quadricostatum", strongylogonum quadricostatum" etc.

Astrophytum myriostigma "quadricostatum" (Four ribbed form)

Astrophytum myriostigma "quadricostatum" (Four ribbed form)

Astrophytum myriostigma "quadricostatum" (Four ribbed form)

A. myriostigma
var.strongylogonum "quadricostatum"

Standard A. myriostigma quadricostatum

Description: A. myriostigma quadricostatum was first described in 1841 by M. Mittler who wrote "The body of the plant is of elongated round form and has four ribs".
This form deviates from the well-known typical form for having four ribs instead of five.
Stem: Quadrangular to almost spherical, the plants become shortly columnar with age. The stems are smooth and can be over 90 cm tall and 5-10 (-20) cm in diameter.
Spines: None.
Ribs: 4.
Flowers: Arise from the areole at the tip of the stem on mature plant. up to 5 cm wide (or more), pale-yellow, shining-silk,unlike the 5-ribbed plant.
Blooming season: Spring or late summer, They take up to 6 years to bloom.

Cultivation is not too difficult in a greenhouse, although grows quite slowly. The plants need  a loose well-drained  mineral soil. They need a good amount of light. Watering can be done weekly during summertime, if the weather is sunny enough, with a little fertilizer added. Kept this way, plants will show a healthy, although slow growth. They are frost hardy to -4° (-10°) C.
 

Propagation: Almost exclusively by seed. Plants are sometimes grafted onto column-shaped cacti.