Coryphantha robustispina ssp. uncinata, 20 seeds
(Coryphantha scheeri var. valida)
Range: far eastern Arizona, southern New Mexico, far West Texas.
 
Skill Level:
Germination: intermediate
Growing: intermediate
 
Origin and Habitat: New Mexico (Garfield, Dona Ana, and Sierra County), USA
Altitude: 6000 ft. above sea level. Coryphantha robustispina subs. uncinata (L.D.Benson) N.P. Taylor has strongly curved or hooked central spines. Distribution (eastern Arizona, New Mexico, extreme West Texas) and Mexico (Chihuahua).Coryphantha scheeri var. valida (Engelm.) L.D.Benson in L.D.Benson: this is the New Mexican form of Coryphantha robustispina subs. scheeri.
 
C. uncinata grows in xerophyllous scrub and grasslands on sandy substrates, alluvial fans, and gravelly soils. It is a slow-growing cactus which should be watered infrequently. Use a loose, fast-draining  mineral soil mix, and keep it dry in winter. Likes full sun but will tolerate some shade. Cold hardy to 20°F. Flowers are yellow with red filaments.
 
Successful germination of cactus seeds is dependent on soil temperature, moisture, cleanliness, and the age and quality of the seeds. It is a common misconception that fresh seeds are best, and while this is true of some species such as Astrophytum and Frailea, many others will not germinate well until they are at least six months old. Cactus seeds can remain viable for up to twenty years if stored in a dark, cool place in your home. Some species have a higher germination rate, and/or a shorter germination time than others. Because there are so many variables involved, a specific success rate can't be guaranteed.
 
Some info courtesy of www.llifle.com