Fig. 6.

Pollen protection and pollen transfer in bilabiate flowers. (A) Phlomis fruticosa, locked lip flower, opened lengthwise. (B) Iris reticulata, meranthium, cut lengthwise to show the upper lip formed by a stylar branch and the stamen and the lower lip formed by a tepal. (C) Camptandra sp., note the lever mechanism formed by the single curved and partly sterile anther. (D) Nemesia anisocarpa with locked entrance. (E) Leonotis leonurus (from below), note the outer part of the lower lip reduced and folded back. (F) Thunbergia grandiflora with locked nectar chamber and anther levers that open the thecae during a visit. (G, K) Columnea tessmannii: flower (G) with fused pollen sacs (K). (H) Salvia pratensis cut lengthwise to show the floral organs and the staminal lever mechanism (a, anther; n, nectar; s, style; sc, sterile connective arm; sl, staminal lever). (J) Thunbergia mysorensis with abbreviated lower lip. (L) representative of the Australian Westringieae with staminal levers coming from the adaxial stamens (upper lip removed). (M) Prunella grandiflora with four downward-orientated anthers. (N) Prunella vulgaris: note the filament formations placing the anthers towards the centre of the flower. (Photographs in G, K: Lars Nauheimer.)