The characteristic glandular crest of "N. stenophylla" is reduced to a small mound under the lid. "Nepenthes lowii" × "N. stenophylla" is only known from mossy forest along summit ridges at elevations of over 1500 m, where the upper altitudinal limit of "N. stenophylla" overlaps the lower altitudinal limit of "N. lowii". A number of other natural hybrids involving "N. lowii" have been reported. These include crosses with "N. hurrelliana", "N. muluensis", "N. veitchii", as well as possible hybrids with "N. hirsuta" and "N. tentaculata". A single example of "N. lowii" × "N. rajah" grows along the Mesilau nature trail. "Ascidia magna, curva, basi inflata, medio constricta, dein ampliata, infundibuliformia; ore maximo, latissimo, annulo O." Nepenthes Lowii, H. f.—Caule robusto tereti, foliis crasse coriaceis, longe crasse petiolatis lineari-oblongis, ascidiis magnis curvis basi ventricosis medio valde constrictis, ore maximo ampliato, annulo O, operculo oblongo intus dense longe setoso. ("Tab." LXXI.) "Hab."—Kina Balu; alt. 6,000–8,000 feet ("Low"). A noble species, with very remarkable pitchers, quite unlike those of any other species. They are curved, 4–10 inches long, swollen at the base, then much constricted, and suddenly dilating to a broad, wide, open mouth, with glossy shelving inner walls, and a minute row of low tubercles round the circumference; they are of a bright pea green, mottled inside with purple. The leaves closely resemble those of "Edwardsiana" and "Boschiana" in size, form, and texture, but are more linear-oblong. I have specimens of what are sent as the male flower and fruit, but not being attached, I have not ventured to describe them as such. The male raceme is eight inches long, dense flowered. Peduncles simple. Perianth with depressed glands on the inner surface, externally rufous and pubescent.