Xerophyte

Leaves

The leaves on Maihueniopsis are very small and fall off early.

Description

Maihueniopsis darwiniiSN|20943]]SN|20943]] is a fiercely spined, mat forming cactus up to 10 cm in diameter and height. The stems may be very tight or lose depending on clones. M. darwinii resembles some forms of O. fragilis in the shape and size of the joints or stems. It also has the ability to spread itself when loosely attached joints break away from the main plant and root wherever they land. It is interesting that O. fragilis has one of the most northern ranges in the cactus family, while M. darwinii has one of the most southern, being from Patagonia at the southern end of South America.

Roots

Enlarged tuberose, with taproots up to more than 30 cm long on plants that appear to be quite small above ground.

Flowers

Solitary larger than the articulations, and very decorative, dirty yellow-orange 2.5-6 cm in diameter. Tepals in about six whorls each of five parts gradually passing from the form of small fleshy bracteal scales to membranous petaloid segments spirally arranged. Filaments numerous covering the inner walls of the fleshy tube. Style remarkably stout cylindrical, stigma very big with about 10 obtuse lobes reaching above the fleshy tube and a little beyond the uppermost stamens. Ovarium a small cell the width of the style surrounded by the very thick fleshy walls of the lower part of tube or floral receptacle. Typically in this species the pericarpel is green and fleshy with areoles placed upous slight tubercular elevations in all the surface each bearing a small fleshy bracteal scale in whose axil is a tuft of yellow tomentum and those on the upper extremity are also furnished with about half a dozen stiff acicular spines (the length of the spines increases from below upwards). M. darwinii is remarkable for the irritability of the stamens, when either a piece of stick or the end a finger is inserted in the flower. The segments of the perianth also close on the pistil, but more slowly than the stamens.

Blooming Season

Late spring to early summer. Flowering is erratic, though well worth the wait.

Spines

Four to six stiff spines of various lengths (2.5 to 4 cm long), and very sharp, present in the upper areoles but absent in the basal areoles of the cladode. Spines have a emphasized central rib with flat margins (winged). They mostly point forward but some spread in all directions.

Stem

Olive-green ovoidal, not tuberculate up to 3 cm in diameter.

Fruits

Fleshy 4 x 2,5 cm similar to the joints for shape and colour. At maturity became yellow-orangish.

Areoles

Approx 4 mm in diameter, circular beset with short white glochids.