Rainbow cactus

Rainbow cactus is a small columnar cactus which is a geographical variety of Echinocereus rigidissimus.

In the fundamental species, Echinocereus rigidissimus, spines on the stem apex are brilliant reddish-purple but the spine is grayish-green as a whole.   The subspecies name, rubispinus, means to have red spines.   And subspecies, rubispinus, is more red than the fundamental species, Echinocereus rigidissimus, and gorgeous.

Raibow cactus is calcifuges and prefers calcium poor and acid soil.   It normally grows solitarily but rarely branches or produces an offset.

The stem grows up to seven centimeters in diameter and thirty centimeters in length with age.   Rainbow cactus is covered with unique reddish-purple spines but does not have any central spine.   There are 30 to 35 radial spines on each areole which are pectinate and curve toward the stem a little.   It is about six to ten millimeters in length.  Its color discolors into yellow or light-pink with age.

The flower is significantly large compared to its stem and becomes ten centimeters in diameter when it is fully grown.   It is brilliant magenta to red and has white throat.  The flowers bloom in ring state on the young areoles on the stem apex.

Rainbow cactus produces dark purple round fruits which contain white pulp and dark brown seeds.   Rainbow cactus hardly produce an offset, therefore, propagates by seedling.

Rainbow cactus is listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix II.

Classification: Cactaceae Echinocereus
Scientific name: Echinocereus rigidissimus subsp. rubispinus (G.Frank & A.B.Lau) N.P.Taylor
Japanese name: ---
English Name: Rainbow cactus
Native locality: Northern Sonora, north-western Chihuahua, Mexco
Ecological description: Evergreen perennial
RDB : CITES appendix 2
Planting place: South and Central America Greenhouse
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