PMC

Nepenthes pitcher and peristome morphology. (A–G) N. bicalcarata. (A) Pitcher. (B) Butterfly (probably Tanaecia pelea pelea) harvesting nectar from the peristome surface. Note the visible line of peristome channels filled with nectar secreted from pores at the inner margin of the peristome (arrow). (C) Underside of inner margin of peristome with tooth-like projections and nectar pores (arrow). (D and E) Peristome surface with first- and second-order radial ridges. Arrows indicate direction toward the inside of the pitcher (F) Transverse section of peristome. Note the transition from the digestive zone to the smooth surface under the peristome (arrow). (G) Inner pitcher wall with digestive gland at the height of the inner peristome margin (H and I) N. alata.(H) Transverse section of peristome. (I) Waxy inner pitcher wall at the height of the inner peristome margin.

The impact of peristome orientation on prey-capture. (A) A phase diagram showing stability and capture properties for varying friction coefficient and peristome tilt with respect to the vertical, , for a model of a flared peristome. Green points are stable, red points slide into the pitcher, and black points slide out. (B) Plots of (green) and (blue) as a function of tilt for the flared peristome, each for varying values of , as indicated. (C) Capture efficiency measure as a function of and varying values of . Measured orientation for N. veitchii is indicated. (D) Efficiency measure as a function of tilt for a fully wetted peristome () for the flared peristome model (bright red) curve and a model of N. jacquelineae (dark red) displaying a less flared and more uniform peristome geometry. Red points slide into the pitcher and black points slide out. Measured orientation for N. jacquelineae is indicated.

(A) LT-SEM image of outer and inner peristome teeth of Brachythecium populeum; (B) close up of the middle region of the outer peristome tooth shown in (A). op: outer peristome tooth; ip: inner peristome tooth; l_o: outer layer of the outer peristome tooth; l_i: inner layer with partly visible ridges; ri: ridges; pa: papillae. Broad arrows: smooth substance coating the papillae and segment borders, with an increasing gradient of coated area from the base to the tip of the outer peristome teeth.

SEM photographs of capsule and peristome of Neodicranella hamulosa: (A) view of capsule, (B,C) views of peristome, (D,E) detailed view of upper part of outer peristome layer (OPL) densely ornamented with distinctive hamulose papillae, (F) detailed view of middle part of inner peristome teeth (IPL) showing conspicuous papillae on cross-trabeculae, (G) detailed view of middle part of outer peristome layer (OPL), and (H) basal part of outer peristome layer (OPL). Scale bars: A–C—100 µm; D—50 µm; E–G—10 µm; and H—50 µm. All photos from holotype (KRAM B-260000).