428 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
12. PENIOCEREUS gen. nov. 
Plants low, slender, erect from an enormous fleshy, turnip-shaped root, usually 4 
or 5-ribbed, rarely 3 or 6-ribbed; spines of all the areoles similar; flowers very 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. 
Type species Cereus greggit Engelm. 
Peniocereus was considered a subgenus of Cereus by A. Berger, whose name we 
have adopted. 
Peniocereus greggii (lngelm. ). Pirates LAXIV, LXNXY. 
Cereus greggui Engelm. in Wisliz. Mem. Tour North. Mex. 102. 1848, 
Cereus pottsii Salm-Dyck, Cact. Hort. Dyck. ed. 2. 208. 1850. 
Cereus greggui transmontanus Engelm. Proc. Am. Acad. 8: 287. 1856. 
Type LocaLity: North and south of Chihuahua, Mexico, 
DistripuTion: Texas to Arizona; Sonora, Chihuahua, and Zacatecas, Mexico. 
Iutustrations: Engelm. Cact. Mex. Bound. pl. 68-65; Schum. Monatssch. Kak- 
teenk. 5: 150, 151; Gesamtb. Kakteen f. 78. 
EXPLANATION OF PLATES LXXIV, LXXV.—PI. LXXIV, A, root; B, plant in flower. Pl. LXXV,A, 
flowers; B, plant in flower, All from photographs taken by Francis FE, Lloyd. 
13. HYLOCEREUS ven. nov. 
Climbing cacti, with elongated, 3-angled or 3-winged stems and branches emitting 
aerial roots, their areoles bearing several short spines and a tuft of very shcrt wool; 
flowers very large, nocturnal, funnelform, the limb as long as the tube or longer; 
ovary and tube bearing large foliaceous scales but without spines, wool, or hairs; 
outer perianth segments similar to the scales of the tube, but longer; petaloid perianth 
segments narrow, acute or acuminate, mostly white; stamens very many, in two 
series equalling or shorter than the style; style cylindric, rather stout, the linear 
stigmas numerous; fruit with several or many persistent foliaceous scales. 
Type species Cereus triangularis (L.) Haw. 
Hylocereus was considered a subgenus of Cereus by A. Berger under this name. 
Hylocereus calcaratus (Weber). 
Cereus calearatus Weber, Bull. Mus. Hist. Nat. 8: 458. 1902. 
Type Locauity: Valley of Tuis, Costa Rica. 
Disrrinution: Costa Rica. 
This species belongs to this genus, not to Selenicereus. 
Hylocereus costaricensis (Weber). 
Cereus trigonus costaricensis Weber, Bull. Mus. Hist. Nat. 8: 457. 1902. 
TYPE LocaLiry: Costa Rica. 
DisrrisuTion: Costa Rica, Central America. 
Older joints gray-glaucous, like those of H/. ecumponis. 
Fylocereus lemairei (Hook. ). 
Cereus lemairei Hook. Bot. Mag. 80: pl. 4814. 1854. 
TypgE LocaLity: Thought to be Antigua. 
Disrrinution: Antigua, Montserrat, Culebra(?), and Porto Rico(?), Antilles. 
ILLUSTRATION: Bot. Mag. loc. cit. 
