Parodia arnostiana

Description

Parodia arnostiana is a species of cactus in the genus Parodia. The small, squat green plants produce yellow flowers, green fruit and black seeds. The species is found growing in Rio Grande do Sul, Brazil. P. arnostiana are green to dark green cacti that are 4 to 6 centimetres (1.6 to 2.4 in) in height, and 4 to 8 centimetres (1.6 to 3.1 in) in diameter. There are between 21 and 30 spiralling ribs, with round areoles topped with white wool. Each areole has from one to three central spines which are yellowish brown to yellowish red in color. There are between 12 and 16 radial spines, which curve, and are from straw-yellow to brownish-red in color. The central spines (which are between 5 and 20 millimetres (0.20 and 0.79 in) long) can be difficult to differentiate from the radial spines (which are up to 7 millimetres (0.28 in) in length). The species produces sulphur yellow flowers (which are between 7 and 7.5 centimetres (2.8 and 3.0 in) in diameter), green fruit (which are between 1.6 and 1.8 centimetres (0.63 and 0.71 in) in length by 1.2 to 1.4 centimetres (0.47 to 0.55 in) wide) and cap-shaped black seeds.