Xerophyte

Central Spines

4-8, the longer ones 40-72 mm, often twisted and somewhat flattened.

Seeds

1,1-1,3 x 0,8-1,2 mm wide.

Description

Echinocereus nicholiiSN|21818]], commonly known as the golden hedgehog, is a big, robust plant with extremely long stems that typically curve upright and form large clusters of as many as 30 stems that can reach 60 tall. The stems are thickly clothed with dense golden spines and creates an almost chartreuse appearance, the hedge-hog colour equivalent of the golden barrel cactus (Echinocactus grusoniiSN|3345]]SN|3345]]). The flowers, while small, are pink or pale lavender, and contrast splendidly with the yellow spines.

Flowers

Inner tepals pink (much paler than those of Echinocereus engelmannii).

Chromosome Number

Echinocereus nicholiiSN|21818]]SN|21818]] is diploid (2n - 22) whereas Echinocereus nicholiiSN|21818]] is tetraploid (2n = 441. This difference in ploidy level represents a reproductive barrier. Hybridization would result in a sterile triploid (2n = 3x = 33), effectively blocking the flow of genes between the parent taxa

Spines

Conspicuously yellow, often golden, relatively monochromatic, the older spines darker, often blackish.

Stem

6-9 cm in diameter, erect to ascending.

Fruits

Remaining spiny after ripening, dehiscent, ovoid, 23-34 mm long, 17-23 mm, the skin green, becoming some-what bronze when fully ripe where exposed to sun, the pulp remaining whitish.

Habit

Branching near ground level, forming clumps often reaching 30-60(-80) cm high and 60-120 cm wide or more with 16-24 or more stems.

Similar Species

Echinocereus nicholiiSN|21818]]SN|21818]] was formerly classified as a variety of Echinocereus engelmannii but differs in chromosome number and a suite of morphologic characteristics. Plants are usually more robust and are easily recognized by their exclusively yellow spines and can be readily separated from E. engelmannii by a greater distance between the areoles on each rib, flowers are somewhat smaller, the inner tepals are pale pink instead of magenta, the basal portion of the floral cup is green instead of coloured, and it has smaller seeds. Echinocereus nicholii more closely resembles Echinocereus ledingii than E. engelmannii.

Blooming Season

Mid- to late spring (in habitat it blooms in March-April and fruits ripen in June)

Radial Spines

8 to 12

Areoles

10-25 mm apart.