Literature
Cact. 4:177
Archiv. Jard. Bot. Rio de Janeiro 2:17-32 (1918)
Gentes Herb. 8:328-345 (1953)
Backeberg 2:726
Kew Bull. 23(2):255-263 (1969)
CSJ(USA) 1975 Yearbook 5-21
CSJ(USA) 50:31-34
NCSJ 21:84, 91; 24:10
KuaS 21(10):181; 28(12):273-278; 38():198; 50(10):244
Bradleya 4:65; 13:74
Sukkde 3:14 (1949)
Krainz 1.8.58, 1.1.62
Gard. Chron. 56:421, 444, 468 (1964)
Plant Dis. 66:602-603 (1982)