MALACOCARPUS. 
187 
Illustrations: Schelle, Handb. Kakteenk. 147. f. 73; Engler and Drude, Veg. Erde 8: pi. 
15, f. 30; Schumann, Gesamtb. Kakteen f. 53, as Echinocactus ceratites; Cact. Mex. Bound, 
pi. 33, f. 7, as Echinocactus sandillon. 
Figure 197 is from a photograph of a plant in the Botanical Garden at Santiago, Chile, 
taken by Mrs. J. N. Rose, in 1914. 
23 . MALACOCARPUS Salm-Dyck, Cact. Hort. Dyck. 1849. 24. 1850. 
Plants globose to short-cylindric, either simple or clustered; ribs definite, usually straight, either 
entire or broken up into more or less definite tubercles; areoles felted, especially when young, spine¬ 
bearing; flowers from the center of the plant, broad and short, mostly yellow; perianth funnelform to 
subrotate; stigma-lobes in typical species red; ovary densely covered with scales bearing an abun¬ 
dance of wool and usually bristles in their axils; fruit soft, rose-red or crimson; seeds brown or 
black, tuberculate with a broad truncate base; hilum white. 
Prince Salm-Dyck, who established the genus, assigned 6 species of Echinocactus to 
it, of which E. corynodes Pfeiffer was the first and is therefore taken by us as the generic 
type. 
Schumann treats the group as a subgenus of Echinocactus; he assigns 3 species to it, 
all from the State of Rio Grande do Sul, Brazil; Arechavaleta, who follows Schumann’s 
treatment, describes 6 species from Uruguay. Besides those heretofore treated in the 
subgenus Malacocarpus, we refer here most of the species assigned by Schumann to the 
subgenus Notocactus. 
We recognize 29 species, all from South America and all found south of the Equator. 
The generic name is from paXatcos soft, and uapiros fruit, referring to the fleshy fruit. 
Key to Species. 
A. Plants globular to stout-cvlindric. 
B. Areoles of the ovary and flower-tube long-hairy or long-woolly. 
C. Spines 4 cm. long or less, straight. 
D. Flowers yellow. 
Ribs acute. 
Spines subulate. 1 _ M. tephracanthus 
Spines acicular. 
Spines yellow. 2. M. schumannianus 
Spines white or becoming silvery. 
Spines 3 to 7. 3. M. grossei 
Spines 9 or 10. 4. M. nigrispinus 
Ribs obtuse or rounded. 
Ribs spirally arranged, broken into tubercles. 
Spirals many; plant gray. 5. M. reichei 
Spirals few; plant brown. 6. M.napinus 
Ribs straight or nearly so, undulate or continuous. 
Perianth short-funnelform. 
Perianth-tube very stout. y. Jtf. apricus 
Perianth-tube relatively slender. 
Plant deeply umbilicate; spines slender. 8. M. concinnus 
Plant slightly umbilicate; spines short. 9. M. tabularis 
Perianth campanulate to subrotate. 
Spines setaceous or acicular. 
Ribs 30 to 40; radial spines up to 40 or more. 10. M. scopa 
Ribs 21 or fewer; radial spines much fewer than 40. 
Ribs very low and rounded. n. M. pulcherrimus 
Ribs prominent. 
Areoles only 4 to 7 mm. apart. 12. M. muricatus 
Areoles more separated. 
Inner perianth-segments obtuse or merely apiculate. 13. M.linkii 
Inner perianth-segments acute or acuminate. 14. M. ottonis 
Spines stouter, subulate. 
Inner perianth-segments 2 to 3 cm. long. 
Spines terete. 
Spines slender, slightly curved. 15. M. catamarcensis 
Spines stout, rigid. 16. M. patagonicus 
Spines flattened. 
Central spines not much longer than the radials. 17. M. erinaceus 
