Xerophyte

Central Spines

None.

Seeds

1 mm in diameter, dark brown.

Description

Eriosyce napinaSN|2370]]SN|2370]] ssp. challensis (Thelocephala) is a marvellous tiny cactus similar to Eriosyce napinaSN|2370]]SN|2370]] var. lembckei but with larger tubers and (maybe) larger spines. It appears white due to its very woolly areoles and addpressed spines that make it looks like an hairy Epithelantha. It is believed to be one of the most beautiful Eriosyce.

Roots

It has a very large fleshy but firm taproot up to 20 cm long and 20-30 mm in diameter and sometimes branched with few shallow roots near the crown.

Tubercles

Less than 1 mm high and very closely arranged in a double spiral pattern.

Flowers

1 to 3 at stems apex, diurnal, funnel-shaped, 25-30 mm long and 20 mm in diameter. Tepals 15 mm long and 3-4 mm wide, pale yellow with a reddish midrib. Pericarpel entirely covered with brown wool. Style, reddish, 18- 20 mm long. Stigma, reddish with 7-10 lobes 3-4 mm long. Stamens 7-15 mm long with yellow anthers.

Blooming Season

Late spring. It blooms already when young, synchronised flowering of the whole plants takes place over one or two days, and flowers remain open for about three or four days.

Stem

Solitary or clustered, globose to elongated eventually becoming somewhat cylindrical in cultivation with a constriction between the stem and the root, 15-30 mm diameter, 40 mm high with a depressed woolly apex extending laterally.

Radial Spines

11-14, about 1 mm long, pectinate, curved towards the body, cream coloured some smaller and orange becoming greys-white as they ages.

Fruits

Rounded to elongate 9-11 mm in diameter and 10-20 mm in length. Completely covered in white wool and silk, and the wool near the base is beige to white. It dehisces (splits open) by a basal pore.

Areoles

Round, not depressed, 1 mm in diameter, younger ones with white wool at the apex