go THE cactaceae;. 



The following varietal names, under Opuntia glomerata var. albispina Forster (Handb. 

 Cact. 472. 184^), \ax. flavispina Salm-Dyck (Cact. Hort. Dyck. 1844. 43. 1845), and var. 

 minor Sakn-Dyck (Cact. Hort. Dyck. 1849. 71. 1850), are mentioned in the places cited, 

 but not described. 



Opuntia horizontalis Gillies (Pfeiffer, Enum. Cact. 145. 1837) was used as a synonym 

 of Opuntia andicola, and should be referred here. 



Opuntia pelaguensis (Salm-Dyck, Cact. Hort. Dyck. 1849. 71. 1850) was published as 

 a synonym of Opuntia platyacantha deflexispina. 



Opuntia andicola minor, an unpubHshed variety, is mentioned by name only in Monats- 

 schrift fiir Kakteenkunde (10: 48. 1900). 



Illustrations: Cact. Journ. i: 100, as Opuntia andicola: Kngler and Prantl, Pflanz- 

 enfam. 3'''': f. 56, K.; Gard. Chron. III. 34: f. 39; Monatsschr. Kakteenk. 13: 23, these 

 three as Opuntia diademata. Cact. Journ. i: February; Diet. Gard. Nicholson Suppl. 

 f. 607 ; Forster, Handb. Cact. ed. 2. f. 125; Gard. Chron. III. 23: f. 129; 2g:i. 63 ; Gartenflora 

 21: pi. 721, f. 2, all as Opuntia papyracantha; Cact. Journ. i: 105, as Opuntia plumosa 

 nivea. 



Figure 104 represents a plant collected by Dr. Rose at Mendoza, Argentina, in 1915. 



Opuntia schumannii Spegazzini (Anal. Mus. Nac. Buenos Aires III. 4: 511. 1905, 

 not Berger, 1904) is a homonym, and we hesitate to give it a new name until it is better 

 known. The type comes from Salta, Argentina, from a region where we already have a 

 number of species of Tephrocactus. Spegazzini, who described it, says it is related to 

 0. diademata, which is now referred to 0. glomerata, but is very distinct. It is without spines 

 and the flowers are unknown. 



Series 4. PENTLANDIANAE. 



Plants often growing in large mounds; joints globular to oblong; spines usually slender, acicular 

 to subulate. Seventeen species are here recognized. 



K©Y TO SpeICIES. 



Spines very long and stout, up to 15 to 20 cm. long 60. 0. aoracantha 



Spines slender, 10 cm. long or less. 

 Spines appressed to the joints. 



Spines 12 to 20, flexuous; joints 7 cm. long 61. O. rauppiana 



Spines 6 or 7; jomts 2 to 4 cm. long 62. O. subterranea 



Spmes straight, not appressed. 

 Spines flat or semiterete. 



Spines 7 to 10 cm. long 63. q. hickenii 



Spines 6 cm. long or less. 

 Longer spines i to 3. 



Joints ellipsoid, 4 to 5 cm. thick 64. 0. darwinii 



Joints oblong, i cm. thick 65. 0. tarapacana 



Longer spines 4 or 5. 



Spines gray 66. O. atacamensis 



Spines yellow 67. O. russellii 



Spines terete. 



Spines white, at least when young. 



Joints tuberculate 68. 0. corrueata 



Joints not tuberculate. 



Joints oblong 69. 0. ovata 



. Jomtsglobose 70. 0. sphaerica 



bpines yellow to brown or nearly black. 



Roots large and woody; spines nearly black 71. 0. skoltsbersii 



Roots fibrous. 



Spines purple-black 72. Q. nigrispina 



bpmes yellow to brown. 



Plants forming large clumps. 



Fruit about 2.5 cm. long, nearly unarmed 73. 0. pentlandii 



Fruit 5 to 6 cm. long, copiously armed with long spines above 74. O. ignescens 



Plants isolated, not forming clumps. 



Old joints globose; spines acicular 75. Q. campestris 



Joints all oblong; spines subulate 76. 0. ignota 



