Frailea castanea is one the of most fascinating cacti. The Latin name “Castanea” means “chestnut” and refers to dark reddish-brown colour of the stem. The flowers are yellow, rather large compared to the rest of the plant, and they have the characteristic of self-pollinate even if the flower remains closed: in fact we are talking about a cleistogama plant. From a single specimen, therefore, it is always possible to obtain fertile seeds for the reproduction of the plant.

Family: Cactaceae (Cactus Family)

Scientific Name: Frailea castanea Backeberg 1936  
Published in: Backeberg & F. M. Knuth Kaktus ABC: 248, 415, 1936.

Distribution: The plant is found from Southern Brazil to Northern Uruguay

Conservation status: Listed in CITES Appendix II

Synonyms: Frailea asterioides Werdermann 1937

Etymology: The genus name "Frailea" remembers the Spanish "Manuel Fraile", born in 1850 who was responsible for the cactus collection of the Department of Agriculture of the United States at the end of the XIX century.
The species name name "castanea" derives from the Latin name “Castanea” which means “chestnut” and refers to dark reddish-brown colour. (the Latin "Castanea" derives  from the Greek. "kastaneia", which meant either "nut from Castanea" in Pontus (eastern Greece) or "nut from Castana" in Thessaly, but probably both places are named for the trees, and the word is probably borrowed from a language of Asia Minor. ( The specific name implies: "coloured like a chestnut").

Frailea castanea is one the of most fascinating cacti.

Description: This is a very singular miniature plant, and one the of most fascinating cacti.
Habit: Disk like, flattened to globose body.
Stem: It is diminutive in size and several remain solitary, never outgrowing 4-5 cm diameter. Stems are chocolate brown or dark reddish-green with 8-15 flat ribs.
Spines: 3-15 minute, short, black spider-like, appressed on the plant body and usually all bent downward.
Flower: Sulphur yellow, sometimes larger than the plant itself (4cm diameter).  But don't be disappointed when the easily produced buds fail to open. 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.
Fruit: Dry  indehiscent that detach easily, pericarp membranous, fragile that break easily releasing the seed.
Seeds: Very big 3-3,5 mm wide.

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).

Propagation:  With fresh harvested  seeds or (rarely) by grafting.

Photo and © copyright by Mladen Turcinovic (Croatia)

Photo and © copyright by Mladen Turcinovicc (Croatia)

Cleistogamus flowers and self pollinated fruits