These are seed grown plants from Christian Klein and are exhibiting extremely dark purple coloration. Nepenthes bongso originates from the Barison range in Sumatra. The species is renowned for producing huge, darkly colored pitchers with a wide, flared peristome. Bongso is a highland plant requiring warm days and cool nights with good light and humidity. Previously, Nepenthes carunculata was designated a separate species but it is now lumped with bongso. Plants designated as var. robusta were some of the most desirable and these plants, though young, have exhibited traits consistent with those.