Coryphantha bumamma

La Coryphantha bumamma è una delle specie più conosciute caratterizzata da un corpo globulare ricoperto da abbondante lana bianca, con tubercoli larghi e spine non offensive. Produce molti germogli tutt'attorno alla base e fiorisce in estate-autunno.

Family: Cactaceae (Cactus Family)

Scientific name: Coryphantha bumamma (Ehrenberg) Britton & Rose
In: Cact. 4:33, 1923

Basyonim: Mammillaria bumamma Ehremberg
In: Allg. Gartenz. 17:243,1849.

Origin:  Mexico (Michoacan and Oaxaca).

Habitat:  Grows in deep fine volcanic soil, among grasses often in cereus forest.

Conservation status:   Listed in CITES appendix 2.

Common English Names include: Elephants Tooth

Etymology: From the Greek word 'koryphe' meaning summit and 'anthos' flower.

Synonyms:

• Coryphantha elephantidens ssp. bumamma (Ehrenberg) Dicht & A. Lüthy
  In: Cact. Syst. Init. 11:14, 2001.A
• Mammillaria elephantidens Shumann
  In: Keys Monogr. Cact. 43, 1903
• Coryphantha elephantidens (Lemaire) Lemaire 1868

C. elephantidens is the centre of a complex of closely related species and it is quite difficult to decide about what is the valid names or eventual subspecies of the different taxon at present time.
The complex comprises:
Coryphantha elephantidens (Lemaire 1838) Lemaire 1868 Coryphantha sulcolanata (Lemaire 1838) Lemaire 1868, Coryphantha recurvispina (De Vriese 1839) Bremer 1976, Coryphantha bumamma (Ehrenberg 1849) Britton & Rose 1923, Coryphantha greenwoodii Bravo 1970 and Coryphantha garessii Bremer 1980.

Coryphantha bumamma is among the best-known cacti, with a  wool covered  globular stem with large, flat tubercles and spines not a real concern. It produces lots of little suckers and bright yellow flowers in later summer to autumn. 

Description: Coryphantha bumamma is a strongly offsetting species forming large groups up to 50 cm in diameter. In adulthood it produces an abundant amount of attractive wool that covers its body. This will wash off if watered from above but will re-grow again. It is very similar to C. elephantidens but the flower are much smaller and nearly yellow.
Roots: It has a stout carrot-like root , almost equal in diameter to that of the stem itself.
Stem: Flattened globular, , broader than high, often (in habitat) arising only a little above the surface of ground, glossy green to bluish-green up to 13 cm in diameter.
Tubercles: Very large up to 27 mm wide and 16 mm tall, always broader than rounded, in 8-13 series, conical flattened , rounded on top, slightly pentaedrical at the base, with a woolly groove on the upper side. The axil in youth is very woolly, later naked. Without glands.
Areoles: Elongate up to 4 mm long.
Central spines: Absent.
Radial spines: The tubercles are capped with a 5-8 of stout, stiff, evenly spreading, reflexed radial spines,16-26 mm long, subulated, curved, never porrect, but adpressed to the body, usually 3 more strong are on the sides greysh or brownish with darker tips
Flowers: Sweet smelling large 5 to 6 cm yellow with reddish midstripe dorsally, inner perianth segments narrowly oblong to lanceolate, margin entire, acute, 5 mm wide, filament reddishat the base, lobes greenish, stigma longer then filaments.
Blooming season: The flowers generally appear mid to late summer.
Fruit: Claviform, very big, ca. 4 cm long, 10-13 mm diameter, whitish green with a reddish tinge.
Seeds: About 4 mm long and 1 mm in diameter, light brown.
 

Cultivation: In culture C. bumamma  is without problems, and regularly shows its large yellow flowers. It does best in slight shade, but does well in full sun too. It is sensitive to overwatering (rot prone), and needs a very porous soil with good drainage.  It flowers quite early, but needs about 8-12 years to reach the typical, definite outlook. It tolerates fairly low temperatures as long as it is kept dry (hardy to -5° C or less for short periods of time).