288 PROCKEDINGS OF THE AMERICAN ACADEMY 



among western travellers as Bill Williams's Fork), and south into 

 Sonora : fl. May - July ; fr. July and August. — A now well-known 

 plant to travellers and botanists, 30- 50 feet high, 1-2 feet in diam- 

 eter ; central spines 1^ - 2| inches long. The yellowish-white 

 flower 3-4 inches long. Fruit 2-3 inches long, often pear-shaped, 

 and opening with 3 or 4 irregular recurved valves. 



30. C. Thukberi, E. in Sill. Journ. 1854: caulibus erectis vel ad- 

 scendentibus pluribus elatioribus articulatis 13 - 14-costatis ; aculeis 

 7—15 gracilibus fusco-atris valde injequalibus ; ovario tuboque im- 

 bricato-squamato ; bacca globosa magna. 



Sonora, west of the Sierra Madre : fl. June and July. — Stems 5- 

 15 from one root, 10- 15 feet high, 4-6 inches in diameter; spines 

 slender, flexible, from 5-18 lines long. Flowers 3 inches long, 

 white. Fruit like a large orange, of delicious flavor. 



Subgen 4. Pilocereus. Caulis elatus : fasciculi aculeorum steri- 

 les a floriferis tenuioribus longioribus distinct! : floris tubus brevis 

 squamosus : phylla pauciora : stigmata pallida : semina Itevia : em- 

 bryo hamatus (in specie nostra !). 



31. C. ScHOTTii, E. in B. C. R. : caulibus erectis vel adscendenti- 

 bus pluribus elatioribus articulatis 4 — 7-costatis ; areolis in articulis 

 sterilibus remotis ; aculeis brevibus robustis, radialibus 4-6, centrali 

 unico ; areolis in articulis floriferis confertis ; aculeis 15-25 longiori- 

 bus setaceis flexuosis e rubello cinereis ; floribus carneis minoribus, 

 tubo gracili decurvo ; bacca parva. 



Sonora, towards Santa Magdalena : fl. July. Stems 8-10 from 

 the same base, often growing in dense clusters, 8 or 10 feet high, 

 with 2-4 articulations, 4 or 5 inches in diameter. Spines of the 

 sterile part of the plant 3-4 lines long, on the fertile joints 1-4 

 inches long, pendulous, forming a reddish-gray beard, in which the 

 flower (not 2 inches long) is somewhat hidden. Seeds large : coty- 

 ledons hooked, exactly as in the last two species. This is evidently a 

 Pilocereus^ but with the seed of a true Cereus, thus reuniting the 

 former with the latter. 



Trib. II. ROTATiE, Miquel. 



Aphylla3 seu folioste. Flores tubo abbreviate subrotati. Cotyle- 

 dones facie versus hilum spectantes seminis lateri contrarian (incum-» 

 bentes). 



