These plants were got by Anatoly N. Evdokimov by purposeful grafting of fragments from a bought Submatucana currundoensis (photo 1). He said that after he had multiplied it vegetatively he paid attention at one of the offsets. It looked like a crest. So he got down to work. First he grafted it onto a good stock. The graft was a success.
Later S.c.f.cristata (photo-2) and S.c.f.monstrosa (photo-3) were got from it. One of these plants had a yellow fragment, it was grafted and gave S.c.f. schike (photo-4), S.c.f.aurea (photo-5), S.c.f.aurea-monstrosa (photo-6) and S.c.f.aurea-cristata (photo -7).
He did not remember how many years it took. Monstrose forms developed from crest turned back to normal and formed several growing points. These forms are more "graceful" - crests are about 3 cm thick, and monstrose forms are only about 1 cm. By the way, monstrose forms can turn back into crested ones.
The question of names is disputable. Probably, it is more correct to call monstrose forms crested-monstrose or just crested. But this is what Anatoly N. Evdokimov called it, and it is really different.
Yellow forms are very demanding - you should watch even tiny changes of stem coloring and the turgor of tissues. S.c.f aurea and S.c.f schike are more stable, though the color of f.aurea changes time to time (the top gets green, the color changes from pale yellow to bright yellow). The coloring of S.c.f.aurea-monstrosa is particularly changeable. It can become, without any apparent reason, bright yellow, yellow-green or light green. At the same time I did not notice any connection with the level of light or other exterior factors. The tissues of yellow forms are very tender, disposed to burns and vermin. In unfavorable conditions they loose elasticity, then get kind of transparent and die. New grafts of healthy by sight tops and fragments most often fail. This is why you should graft a healthy plant (multiply vegetatively) not to be afraid to spoil a collection plant.
Trichocereus pachanoi showed itself as a good stock for these plants. Though they are grafted well on other stocks too.
P.S. S.c.f.schike - this is how Anatoly N. Evdokimov called yellow-green variegated forms of cacti.
Plants on photos 4, 6 and 7 are from Anatoly N. Evdokimov's collection. The rest belong to Alexander Berezuev. Photos by Sergey Berezuev.