92 F- Fedde und K. Schuster: Index novarum Siphonogamaium. [92 



Pachycereus queretarensis (Weber) Britton and Rose 1. c. p. 422 (= Cereus 

 queretarensis Weber). — Mexiko. 



P. titan (Engelm.) Britton and Rose 1. c. p. 422 (= Cereus titan Engelm.). — 

 Lower California. 



Peniocerens Britton and Rose gen. nov. in Contrib. U. S. Nat. Herb. Washington 

 XII (1909). p. 428. 



Plants low, slender, erect from an enormons fleshy turnip shaped 

 root, usually 4 or 5-ribbed, rarely 3 or 6-ribbed; spines of all the areoles 

 similar; flowers verj large for the size of the plant, only one from a 

 Single areole, nocturnal, white or tinged with red; tube of flower long, 

 slender, with small Clusters of spines scattered over the outer surface; 

 fruit ovoid, long-acuminate, bright scarlet, fleshy and edible with elevated 

 spineless areoles; seeds black, rugose, with a large oblique hilum. 



Peniocereus was considered a subgenus of Cereus by A. Berger, 

 whose name we have adopted. 



P. Greggii (Engelm.) Britton and Rose 1. c. p. 428. PIs. LXXIV. LXXV 

 (= Cereus Greggii Engelm. = C. Pottsii Salm-Dyck = C. Greggii trans- 

 montanus Engelm.). — Mexiko. 



Pereskia autumnalis (Eichlam) Rose in Contrib. ü. S. Nat. Herb. Washington 

 XII (1909). p. 399. PI. LH. LIII. LIV (=^ Pereskiopsis autumnalis 

 Eichlam). 



Rathbnnia Britton and Rose gen. nov. in Contrib. U. S. Nat. Herb. Washington 

 XII (1909). p. 414. 



Plants not large, the stem and branches often weak; spines stout, 

 those of the flowering areoles not differing from the others; flowers 

 diurnal, Single from the areoles, very narrow and elongated, trumpet- 

 shaped, somewhat curved, oblique at mouth, scarlet; petals very short, 

 spreading, reflexed, or rolled back; stamens inserted near the middle of 

 the tube, exserted; fruit globular; seeds black, compressed, minutely 

 pitted, with a large basal oblique hilum. 



R- alamosensis (Coult.) Britton and Rose 1. c. p. 415 (= Cereus alamosensis 

 Coult.). — Alamos, Sonora. 



R. Kerheri (Schum.) Britton and Rose 1. c. p. 41.5 (= Cereus Kerheri Schum.). 



— Mexiko. 



R. sonorensis (Runge) Britton and Rose 1. c. p. 415 (= Cereus sonorensis Runge). 



— ibid. 



Selenicereus Britton and Rose gen. nov. in Contrib. U. S. Nat. Herb. Washington 

 XII (1909). p. 429. 



Sterns slender, trailing or climbing, elongated, with low ribs, 

 giving off roots irregulary; flowers large, often very large, nocturnal; 

 bracts of ovary and flower tube usually bearing long hairs and bristles; 

 fruit large, reddish, covered with Clusters of deciduous spines. 



Selenicereus was considered a subgenus of Cereus by A. Berger under 

 this name. 

 S. Boeckmanni (Otto) Britton and Rose 1. c. p. 429 (= Cereus Boeckmanni Otto 



= C. eriophorus Griseb.). — Cuba. 

 S. coniflorus (Weingart) Britton and Rose 1. c. p. 430 (= Cereus coniflorus 



Weingart). — Haiti. 

 S. grandiflorus (L.) Britton and Rose 1. c. p. 430 (= Cactus grandiflorus L. 

 = Cereus grandiflorus Mill.). — Jamaika, Vera Cruz. 



