C. humboldtii is native to "Brazil and adjacent Venezuela in the Casiquieres district (Madison, 1981)." Also,"this species...was observed being grown by the residents of Vega de Oropouche [Trinidad] in 1988. ...Although the owners insisted that their plants were collected locally, we were unable to convince them to show us plants in the wild. C. humboldtii is cultivated in the U.S. and Europe and may hve been sold commercially in Trinidad in the past (Boos & Boos, 1993)."

The inflorescence has never been seen. In the greenhouse, the blade of the leaf is 10-14 cm long and 4-7 cm wide. My plants have petioles that are up to 40 cm long. This is much longer than the numbers usually given for the species (10-25 cm). The etiolation of the petiole may be a result of certain wavelengths of light being blocked by the fiberglass cover of the greenhouse.