Subgenus NOTOCACTUS

thick and long columns; soft, fine bristle like, equally thick spination. The lowest central spine is the longest; stigma always yellow; apex tilted towards the main light source; Flowers 5 cm to 9 cm wide. At maturity the fruit is completely filled; it opens from the base with a transverse ring like tear, to such an extent, that the main part of the fruit is removed and only a small part of the shell remains on the Areole. The empty fruit skin is stable over long time. Testa covered with a transparent, however hardly recognizable firmly adhering aril skin, which is only removed with difficulty without damaging the testa. The testa tubercles are clearly convex and glossy, but are largely concealed by the aril skin; which makes the testa appear smooth.

Subgenus BRASILICACTUS

apex slants at maturity towards the main light source; Very numerous needle-like translucent spines, without distinctive central spines. Very small Flowers (to 3 cm), reddish, yellow or greenish. Fruit small, spherical, not woolly. Seeds clearly different from the seed of related sections, essentially small, extended curved bell shaped, heavily tuberculate, with glossy black larger tubercles, which are arranged in rows at the base.

Subgenus NOTOBRASILIA

bodies soft fleshed, sometimes turning reddish; Ribs are composed of mamilliform tubercles, areoles sit on the tubercles; lower Central spines tortuous to hooked; flowering period in spring mornings; Bud tips in the early stages bare. Flowers 3 to 5 cm wide

Subgenus MALACOCARPUS

plants hard fleshed, the apex very distinctively wooly. Ribs greatly thickened at the areoles, tubercles chin like. Areoles on the underside of the tubercles, strong areolar wool; Flowers sunken in the apical wool; Fruit tube shaped, very soft at maturity and thin-walled, ripens in the spring after flowering; not rupturing. At least half of the fruit remains in the apical wool; when ripe the funicle (seed thread) swells, therefore remaining soft fleshed after the basal stretching; whitish green, usually pink or reddish in color. The fruit wall becomes brittle. The seeds are completely covered with a brown aril skin.

Subgenus GYMNOCEPHALUS

bodies mostly soft fleshed; funnel-shaped flower tube; Fruit soft fleshed; flowering period morning to afternoon. Flowers of 2 cm to 13 cm wide

Subgenus NEONOTOCACTUS

bodies mostly hard fleshed; flower tube expands over the ovary to form a bell shape; Fruits at maturity form a tube; flowering period in the afternoon; Flowers 3 cm to 13 cm wide