Parodia herteri

Parodia herteri is a small cactus in the Cactaceae family. It also bears the older name Notocactus herteri. Its native range spans southern Brazil and Uruguay. In Brazil, it grows in Rio Grande do Sul. This succulent comes from a subtropical region with open grasslands. Wild plants grow in sandy, rocky ground at low elevations. Its range is small, and some local groups have disappeared.

The plant often grows as a single rounded stem. It may branch slowly from the base as it ages. Older stems can form a short cylinder. They reach about 0.5 feet [0.15 metres] tall and wide. The skin is glossy and deep green. About 22 clear ribs spiral around the stem. Raised bumps give these ribs a chinned shape. The sunken crown has pale grey-white wool. Wool also fills the recessed areoles, then fades with age. Each areole bears eight to eleven thin, flexible radial spines. These are white with brown-red tips. The thicker central spines start reddish brown and turn grey.

Flowers grow near the top of the stem. Their colours range from pale violet-pink to deep purple. Each flower has a white or yellow centre. Narrow petals have light fringes along their edges. A darker line marks the tip of each petal. Golden anthers surround a pinkish stigma with ten lobes. LLIFLE lists the bloom season as July to September. Its flower notes also mention spring, so the timing remains unclear.

This cactus suits a home or greenhouse with bright, filtered light. It also needs good airflow around the stem. Give it regular water during summer growth. Keep its short winter rest cool and dry. Long dry spells can cause root loss. Cold, wet compost can also harm roots and cause rot. LLIFLE reports frost tolerance down to −4°C, but favours added warmth. It recommends rainwater and an acidic compost. Iron feed may help delay corking at the stem base.

Growers keep this species as an ornamental in cactus collections. They raise it mainly from seed because offsets are rare. Fire, farming, forestry, grazing, and urban growth threaten wild plants. Some local collecting adds pressure to its small range. The supplied sources give no details on fruit or animal pests. They also give no evidence about food use or toxicity.