Xerophyte

Central Spines

Absent or 1, rarely 3, upright-projecting, yellowish-white to almost black , but in age grey, more or less annulate, 5-50 mm long.

Seeds

Pyriform black, 1,4-2 mm long, 1-1,8 mm in diameter, seed-coat net-like.

Description

Thelocactus leucacanthusSN|1067]]SN|1067]] is a cushion forming cactus. It clusters very easily and in the wild it may form groups up to 80 cm in diameter with hundreds of heads. The flowers open on the day and the colour varies from pale yellow to pink depending on the variety and clone. The flowers last for several days but close every night. T. leucacanthus is extremely variable in the number and length of its spines.

Tubercles

Conical-obtuse with rounded tip, 8-11 mm tall,. 10-14 mm wide.

Flowers

Diurnal, funnel-shaped 2,5-5,2 cm long, 2-4,5 cm in diameter, the colour varies from pale yellow to pink (or magenta ) depending on the variety and clone. They are produced on the apex of the youngest tubercles and are furnished by scales. Inner perianth-segments numerous, lanceolate, acute. Tube short. Ovary and flower-tube bearing broad imbricated scales. Filament yellowish-green, anthers yellow, style pale magenta with 5-6 stigmatic lobes.

Blooming Season

The Thelocactus leucacanthusSN|1067]]SN|1067]] blooms at the end of spring.

Ribs

7-14 tuberculate but well-defined, straight or sometimes spiralling.

Stem

Simple then clustering freely, light green globular or short-cylindric, 4.5-15 cm tall, 2.5-6 cm in diameter.

Radial Spines

6-20 unequal, 5-7 (or more) mm long, spreading or moderately recurved, at first yellowish-white becoming reddish to greyish as they age.

Fruits

Furnished of scales, dark green to yellowish sub spherical 6-9 mm in diameter that dry at maturity. Dehisces basally and conserve the floral remnant.

Areoles

Elongated 6 x 3 mm wide, spaced 4-6 mm. Positioned on the top of the tubercle and furnished with with nectar-secreting glands.