Commemorating Dr Domingo Parodi (1823–90), pharmacist and student of the flora of Paraguay.
Body solitary or clustering with stems ribbed or tuberculate. Spines variable. Flowers diurnal, arising at the body apex, funnel-shaped, brightly coloured; spring to summer. Pericarpel and flower tube with narrow scales bristly in their axils. Fruit spherical to club-shaped, splitting longitudinally or at the base. [Blossfeldia Werderm., Eriocactus Backeb., Brasilicactus Backeb., Brasiliparodia F. Ritter, Notocactus of Backeb. and Wigginsia D.M. Porter]
A genus in need of revision with many poorly defined species and considered here in a broad sense including all the genera listed above.
Species not included in the key and sometimes available include: P. aureicentra Backeb. from N Argentina which has 4-12 extremely long, curved central spines. [P. rauschii Backeb. invalid]; P. claviceps (F. Ritter) F.H. Brandt which is rather similar to P. schumanniana (Nicolai) F.H. Brandt but with pale yellow bristly spines; P. columnaris Card. from Bolivia with pale yellow flowers; P. comarapana Cárdenas (probably P. saint-pieana Backeb.) from C Bolivia with similar central and radial brown-tipped spines; P. dichroacantha Brandt & Wesk with red flowers or bright yellow flowers suffused red; P. herteri (Werderm.) N.P. Taylor which is like P. rutilans but with ribs about 1 cm deep; P. laui Brandt from Bolivia with relatively few areoles per rib and salmon to red flowers; P. maassii (Hesse) A. Berger which has red to yellow flowers with a woolly tube; P. mutabilis Backeb. from N Argentina with 20-40 or so extremely fine radial spines and bright yellow flowers. [P. aureispina Backeb.]; P. ottonis (Lehmann) N.P. Taylor which is like P. horstii but has orange to reddish or purple flowers; P. procera F. Ritter from Brazil with yellow flowers; and P. subterranea F. Ritter from Bolivia which grows to about 5 cm wide and has deep red flowers.
Flowers near the crown and brightly coloured, flower tube short with woolly, hairy and mostly bristly scales; fruit more or less spherical. Many species have at least a few hooked spines. The similar genus Frailea is generally smaller (bodies less than 5 cm wide) and with closed flowers.
About 40-50 species from S America.
Source: (1997). Cactaceae. In: . Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.
