Xerophyte

Seeds

Cap-shaped, 2 mm long and 1.5 mm wide, smooth and shiny, brown.

Note

This member of the Cactaceae family was given this name for Melita Horst, wife of the Brazilian plant collector Leopoldo Horst.

Flowers

Funnel-shaped, 27 mm long and up to 37 mm wide when open, shiny golden yellow. Corolla tube, with tawny hair and up to 8 mm long bristles overgrowing the receptacle. Inner wall of the receptacle red at the base, outer receptacle wall covered with scales, bristle and hair. Petals, golden yellow, spathulate, pointed at the ends, upper margin finely notched. Style white. Stamens white, red in the lower part. Anthers yellow.

Spines

Thin, straight, glassy white, a little stronger and light brown at the base, deciduous or persistent. Radial spines pectinated up to 4 on each side, 3 to 4 mm long, at times with a small central spine 3 mm long.

Ribs

Up to 21, quite flat divided by transverse depression into tiny tubercles, darker V-shaped , blots can be seen below the areoles.

Stem

Solitary, not clumping, globular, rootstock conical sunk into the earth, 1.5 cm tall and to 4 cm in diameter, dark olive-green to brown or purplish.

Fruits

Fruits 9 mm long, 8 mm wide covered by light yellow bristles and white hairs.

Areoles

With conspicuous, glassy white wool, later glabrous.