Iris dichotoma flowers, the Vesper Iris, formerly Pardanthopsis, open ‘religiously’ in the afternoon around 4 pm. By late evening, they are already withered. Nonetheless they are beautiful and it is exciting to watch. It makes you wonder – why the short period of flowering?

According with an article from the Journal of Experimental Botany: “flower opening and closure are traits of a reproductive syndrome, as it allows pollen removal/and or pollination”. Although a peculiar species, the vesper iris is not given as an example in the study.

Iris dichotoma – first year flowering from seeds; super easy to grow

Those interested can read about the mechanism of opening and closure, carbohydrate metabolism, hormonal regulation and more here – Flower opening and closure: a review, Wouter G. van Doorn, Uulke van Meeteren.

Note on Vesper
In many Christian denominations, vespers is the name used for the evening prayer service. From Greek ‘hespera’ and Latin ‘vesper’ = evening.