Passage: third, becoming widely infundibular above. They are relatively small, rarely exceeding 5.8 cm in height and 4.4 cm in width. Fringed wings (≤2 mm wide) are usually present in terrestrial pitchers. The pitcher mouth is almost horizontal. The inner surface of the pitchers is glandular throughout. The flattened peristome may be up to 8 mm wide and is lined with a series of teeth (≤0.5 mm long) on its inner margin. The lid or operculum is narrowly obovate, and up to 3.8 cm long and 1.3 cm wide. The undersurface of the lid bears scattered small red glands that are concentrated around the midrib. Around 20 to 30 very large crater-like glands (≤0.5 mm wide) are present in the apical quarter. These glands are so large that they are visible as swellings on the upper surface of the lid. The spur (≤4 mm long) is inserted at the base of the lid. It is generally unbranched but may be forked.

Question: What is the shape of the inner surface of the pitcher?
glandular