Fig 1.
Flowering phases and UV-reflectance properties of Crocus species.
(A) Flower of the saffron crocus C. sativus in the early flowering phase with a syrphid fly, Episyrphus balteatus, targeting at the stigma. (B) The same flower in the subsequent flowering phase with a syrphid fly feeding on pollen. (C) Western honeybee, Apis mellifera, landing on a Crocus flower and targeting at the stigma. (D–G) Colour photograph and UV-photograph of violet and yellow garden crocuses.
Fig 2.
Reflectance properties of differently coloured Crocus flowers.
Relative spectral reflectance of tepals in the yellow-flowering C. chrysanthus and C. flavus and the violet- or white-flowering C. vernus.
Fig 3.
Comparison of reflectance properties of some yellow-coloured Crocus species.
Colour photograph, UV-photograph and relative spectral reflectance of tepals are shown for five exemplary yellow-flowering Crocus species. Note that only in C. korolkowii parts of the tepals are distinctly UV-reflecting.
Fig 4.
Style length dependent on stamens length in relation to perigone colour.
Analysis of 106 Crocus species regarding perigone colour. Both style length and stamens length are relative to the length of the tepals.
Table 1.
Longest reproductive organ in Crocus species.
Numbers of differently coloured Crocus species in which the style length surpasses the stamens’ length, vice versa, or both organs have the same length.
Fig 5.
Mean relative length of style compared to stamens for Crocus species with different perigone colours.
With standard error; n = 106 species of Crocus comprising 48 violet, 22 violet/white, 19 white and 17 yellow coloured species.
Fig 6.
Phylogenetic tree of the genus Crocus with superimposed floral characters.
Phylogenetic tree obtained by Bayesian phylogenetic inference of the nuclear rDNA ITS region. The floral characters indicated are flower colour and relative style length as compared to the relative stamens length and branching of the style for 106 Crocus and 3 Romulea species.