I30 



THE CACTACEAE. 



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TRICHOCEREUS 



1909 



S J Columnar plants, more or less branched ; ribs few to numerous, either low or promment, usually 



very spiny; flowers nocturnal, large, funnelform. the perianth either persistent or separating from 

 the fruit by abscission; perianth-segments elongated; stamens numerous, fihform arranged m two 

 groups ; stigma-lobes numerous; ovary and flower-tube bearing numerous scales, their axils bearing 

 long hairs; fruit without bristles or spines, dull colored. 



Type species: Cereiis macro gonus 0\X.o. , . 



>ri,;^ „..„,ic r^/^ncJc+c of Tn <;npHp«; rnnfined to South America. It is based on the sub- 



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Riccobono. 



While the flowers of this genus suggest Echinop 



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name is from the Greek and signifies thread-cereus, referring to the hairy 



areoles. 



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Key to SpEcms. 



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Stems more or less branched, usually erect. 

 Limb of flower broad. 



Joints relatively slender, 5 to 9 cm. thick. 



Ribs transversely sulcate between the areoles. " ^ , 7 



Tubercles prominent. i- ^' thekgonus 



. Tubercles not prominent 2. T, thelegonotdes 



^ ^ ' • Ribs not transverse! v sulcate between the areoles. 



\ - .. Central spine solitary 3- T. spachianus 



■ '*^ ' Central spines 4 ." 4- T. lamprochlorus 



■ ** Joints stout. ^ 

 ■ ■':.' Ribs on old plants very numerous and the spines bristle-hke 5- -^ • pasacana 



„, , Ribs 4 to 17. / % : 



Spines slender, i to 7 cm. long. 



Ribs 4 to 9. ' 'J " 



i ' : Spines yellow, at least when young; ribs 4 to 8 6. T. bndgesii 



^" - ■ ^ * "^ Spines brown from the first; ribs 6 to 8. 



Plant dark green; spines few at each areole or wanting 7- T, pachanot 



Plant light green; spines several at each areole. 



Spines acicular, 2.5 cm. long or less 8. T. macrogonus 



Spines subulate^ up to 7 cm. long. 



Spines swollen at base; young growth green 9v ^- cuzcoensts 



Spines not swollen at base; young growth very 



. . , glaucous : 10. T. peruvianus 



: Ribs 16 or 17 \ . .-. . : . . ;. . : u. T. chiloensis 



Spines very stout, formidable. -. ■ * _ . . ... 



. Spines dark brown. .^•. ........ i^,,. 12. T. coquttnbanus 



Spines yellow. '13 T. ierscheckii^ 



Limb of flower narrow 14. T. fascicularis 



Stems usually simple, low', cespifose. ' \ T 



Flowers red or yellow, short, more or less campanulate. :/. :.\ ; . : '.'. . . . .'. ..... V. . ...... 15- ^- huascha 



Flowers elongated, funnelform, white. ^ ; .^- ' t .' - , " 



Tube longer than the limb. ^' ^ . 



Ribsfew. 9 to fr. :....;.. \... ............:.. .. '. .:..*: .?.i6. r. candkans 



Ribs 12 to 18. ' '^ , ' 



Stem slender, elongated. , ... .1 '. 17. T, strigosus 



Stem stout, short !..;.... 18. T. shaferi 



Tube about the length of the limb . . . 19. T. schkkendantzit 



1. Trichocereus thelegonus (Weber). 



Cereus Ihekgonus Weber in Schumann, Gesamtb. Kakteen 78. 1897. v 



Stems procumbent or sometimes with erect branches, elongated, 4 to 10 dm. long, dark green, 

 cylindric, 4 to 7.5 cm. in diameter; ribs 12 or 13, broad and obtuse, divided into prominent, more or 

 less distinctly 6-sided tubercles; areoles circular, felted; spines at first brown, some turning gray, 

 others black; radial spines 6 to 8, acicular, somewhat spreading, i to 2 cm. long; central spine solitary, 

 porrect, 2 to 4 cm. long; flowers white, about 20 cm. long, funnelform; outer perianth-segments 

 greenish; axils of scales on flower-tube long-woolly; fruit about 5 cm. long, hairy, red, splitting on 

 one side; seed black. 



Type locality: Tucuman, Argentina. 



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Distribution: Northwestern Argentina. 



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