Nectar secretion

Nectar is produced in glands at the base of the stamens. In species with a long anthophore the places of nectar secretion and nectar deposition are not the same. If a stipe is present nectar is secreted into 10 crypts which starting from the gaps between the free filament bases conduct the nectar down the stipe towards the base of the calyx tube (Vogel, 1998). If the stipe is lacking or very short the nectar collects directly at the bottom of the calyx, there it is accessible for nectar-seeking flower visitors.

The secretion of nectar at the base of the filaments makes it possible for nectar-seeking insects to find nectar not only at the base of the flower but also in a shorter distance from the flower entrance along the anthophore. Therefore, in species with anthophore nectar is accessible to a wider range of flower visitors and even insects with shorter tongues may reach some nectar when they push their head or body more deeply into the flower tube. Thus, it can be assumed that species with a long anthophore instead of a long ovary and/or style follow a mixed strategy offering nectar to a wider range of flower visitors. Nevertheless, nectar is accumulated at the base of the flower and if present flower visitors with a long tongue will probably gain the main supply.

S. dichotoma anthophor with nectar droplets	S. succulenta with long anthophor and nectar in crypts	S. laeta with short anthophor
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S. muscipula anthophor with nectar droplet at base	S. nutans anthophor with nectar	S. conoidea with short anthophor

Vogel S. 1998. Remarkable nectaries: structure, ecology, organophyletic perspectives III. Nectar ducts. Flora 193: 113-131.