Frailea grahliana is a common tiny and heavily clumping species that in cultivation can easily fill a 15 cm pot. It grows quickly. and  tiny has dull green to purplish stems and short yellowish or brownish spines.

Family: Cactaceae (Cactus Family)

Subfamily: Cactoideae

Tribe: Notocacteae

Accepted Scientific Name: Frailea grahliana (F.Haage) Britton & Rose 1922

Original pubblication: Echinocactus grahlianus Haage jr.
In: Schumann, Monatsschr. Kakteenk. 9: 54. 1899.

Distribution: Paraguay, Argentina.

Habitat:  Grows on flat sandstone at the edge of plates rocks or on clayey soil among sandstone fragments, both in open an sunny spots and under grasses. The climate is warm and humid with hot summers and much thaw during the night. The winters are also warm even so occasionally light frosts may occurs, but the sandstone rocks warmth during the day and give off heat at night so rarely the temperature at soil level go below 5°C. It grows in association with Bromelia serra, Cererus lanosus and Monvillea sp. (paxtoniana?) that forms snake like stems.

Conservation status: Listed in CITES Appendix II

Synonyms:

• Cactus grahlianus Kuntze
  In: Deutsch. Bot. Monatsschr. 21:193. 1903

• Frailea grahliana ssp. concepcionensis

• Frailea moseriana

• Frailea grahliana ssp. moseriana

• Frailea grahliana ssp. grahliana

Was in 1897 recorded in the catalog of Haage, under the name of Echinocactus schilinzkyana var. grandiflora.

Frailea grahliana
It has dull green to purplish stems and short yellowish or brownish spines.
Flowers will open only in great heat on the hottest, brightest, sunny afternoon, if at all.

Description: Frailea grahliana is a common tiny and heavily clumping species that in cultivation can easily fill a 15 cm pot. It grows quickly. This specie is known from a very long time and its taxonomic status is quite confuse. In habitat there are intermediate form with F. pumila and F. friederichii and some botanists consider the different plants of this polymorphic group as F. pumila.
Stem:  Dull-green, brownish-green to dark purple-green, top-shaped, depressed-globose, 3-4 cm in diameter and clumping around the base.
Root: Fleshy yellowish.
Ribs: About 13 to 15 low and indistinct.
Central spines: Absent.
Radial spines: 8 to 11 yellowish, subulate, flattened on the surface, appressed and curved backward, 3-5 mm long.
Flowers: Pale to bright yellow , up to 4 cm long. Fraileas are cleistogamous meaning that their flowers produce seed without even opening. Without the need for pollination, hence the buds rarely reach full bloom and remain closed. They will open only in great heat in the hottest, brightest, afternoon sun, if at all.
Fruits: 6 mm in diameter, dry indehiscent with scales and bristles that detach easily, pericarp membranous, fragile that break easily releasing the seed. This species sets fruits without opening the flowers (cleistogamy)
Seeds: Brown, smooth.

F. grahliana is an heavily clumping species.

Cleistogamous and normal Buds

Cultivation:  Grow them in rich, porous soil and let them dry out between waterings.  These plants need a minimum temperature of 5-10° C (but occasionally temperatures of a few degrees below 0° are not dangerous)
Sun Exposure:  It enjoys full sun, and it can take on a near black appearance when kept in bright light.  In a shaded position the plants grow faster, but are not flat shaped and dark coloured.
Characteristically, during the dry season plants retract completely under the ground both in the wild and in cultivation too.

Notes: This plant is short living (It does not live long - about 10-15 years).