First description was:

 Britton & Rose's The Cactaceae

9. Trichocereus cuzcoensis sp. nov.

Synonyms

Description:
   Plants tall, 5 to 6 meters high, much branched, the branches somewhat spreading, light green when young;
ribs 7 or 8, low and rounded;
areoles rather close together, 1 to 1.5 cm. apart;
spines numerous, often 12, very stout, rigid, sometimes 7 cm. long, swollen at base;
flowers 12 to 14 cm. long, doubtless noc­turnal but, sometimes at least, remaining open during the morn­ing, fragrant;
flower-tube green, 5 to 6 cm. long;
inner perianth-segments oblong, white, 4 to 5 cm. long;
filaments weak, de­clining on the lower side of the throat;
scales on the ovary and flower-tube small, bearing a few long hairs in their axils;
fruit not known.

   Collected by J. N. Rose below Cuzco, Peru, Sep­tember 1, 1914 (No. 19022).