THE CACTACEAE. 



about 20 cm.; outer perianth-segments linear, pointed, reddish brown, the inner perianth-segments 

 narrowly lanceolate, 7 cm. long, 12 to 15 mm. broad, acute; filaments numerous, weak, white; style 

 long and slender, exserted beyond the withering perianth; stigma-lobes slender, white, entire; 

 scales on the ovar\- and flower-tube minute, i to 1.5 mm. long, reddish brown, bearing white felt 

 and white bristles in their axils; fruit crowned by the ^^•ithe^ing perianth, globular, 2 to 2.5 cm. in 

 diameter, reddish, bearing numerous, small, circular areoles, these with clusters of acicular spines 

 sometimes i cm. long. 



Type locality: Southern IMexico. 



Distribution: Mexico, but range not known. 



We have had this plant under obser\^ation since 19 14 when cuttings were sent us 

 by C. Z. Nelson, an enthusiastic grower of cacti at Galesbm^g, Illinois, who obtained it 

 from southern Mexico from Dr. J. L. Slater. This plant made two flowers during the week 

 of May 17, 1922; the fruit ripens very slowly and did not mature until October 10, 1922. 



According to Wilhelm "Weingart, the same species has long been grown by Frantz 

 de Laet at Contich, Belgium, also from INIexican material. 



Illustration: Zeitschrift Sukkulentenk. i: 33, as Cereiis nelsonii. 



Figure 261 shows a branch bearing a newly matured fruit. 



'•7'" 





Fig. 261. — Selenicereus nelsonii. 



On page 216, vol. 11, under Werckleocereiis tonduzii, add: Illustration: iSIonatsschr. 

 Kakteenk. 31: 85, as Cereus tonduzii. 



On page 218, vol. 11, under Aporocactus leptophis, add to illustrations: Ann. Fl. Pom. 

 1839: pi. 43, as Cereus leptophis. 



On page 219, vol. 11, under Aporocactus flagellijormis, add to illustrations: Tribune 

 Hort. i: pi. 4, as Cereus serpentimts; Fl. Antill. i: pi. 67, as cierge queue de souris; Cact. 

 Joum. i: 82; Rother, Praktischer Leitfaden Kakteen 57; Remark, Kakteenfreund 6; 

 Watson, Cact. Cult. ed. 3. f. 11; FloraUa 42: 371; Gartenwelt 15: 637; Blanc, Cacti 27. 

 No. 104; Amer. Gard. 11: 527 as Cereus flagellijormis ; Cact. Joum. i: 125; 2: 34; 2: 153, 

 as C. flagelliformis cristatus. 



Insert: Cereus smithiamis is a hybrid listed by Sweet (Hort. Brit. ed. 2. 237. 1830) 

 which the Index Kewensis refers to C. smithii, a generic hybrid already referred to. 



On page 221, vol. n, tmder Aporocactus martianus, add to the illustrations: Thomas, 

 Zimmerkultur Kakteen 14, as Cereus martiamis. 



