Fragrance Fragrance is an important feature of the pollination strategy in many species of Gladiolus. All moth-pollinated species of the genus produce a strong, sweet scent, usually with an undertone of cloves. The scent may be present throughout the day and night, as in G. emiliae (section Linearifolius), G. robertsoniae (section Hebea) and G. recurvus (section Homoglossum). In the moth-pollinated species, G. liliaceus, G.

longicollis and G. tristis of section Homoglossum, scent is produced only in the evenings. Scent production is accompanied by a shift in perianth colour from dull brown or red to pale mauve in G. liliaceus, a particularly unusual phenomenon.Bee-pollinated species do not depend on fragrance to attract visitors to the same extent as do species pollinated by moths. Nevertheless, most bee-pollinated species of the predominantly winter-rainfall sections Hebea and Homoglossum produce strong, sweet odours, whereas bee-pollinated species of sections in the summer-rainfall region do not produce scent. Species of section Linearifolius which are pollinated by bees produce scent inconsistently. The winter-rainfall Gladiolus brevifolius and summer-rainfall G.

pubigerus produce scent in some populations. Fragrance in section Hebea is characteristically very strong and is a combination of violet and freesia. In the field, flowers can often be located by scent before they are seen. Particularly strongly scented species are the cryptically coloured G. orchidiflorus and its allies, G. ceresianus, G. uysiae and G. watermeyeri.

Gladiolus permeabilis subsp. permeabilis is usually scented and subsp. edulis frequently so, with most populations north of the Vaal River being unscented, whereas strongly scented populations occur in the Karoo, Free State and Namibia. In section Homoglossum the southwestern Cape species G. carinatus and G. gracilis are well known for their highly fragrant flowers, but perhaps the finest fragrance is produced by G. trichonemifolius. In the nineteenth and early twentieth centuries the flowers of these species were treasured for the vase and a few stems will fill a house with their delightful fragrance.

The source of floral fragrance in Gladiolus has received little study. We suspect that the fragrance comes from the papillae on the lower tepals and the upper part of the perianth tube. These papillae are prominent in species that produce scent and can be stained with ruthenium red, a dye that is an indicator of lipid production. In sections Homoglossum and Hebea lines of papillae are most often present on the areas of pale or yellow pigmentation on the lower half of the lower tepals, but papillae are also present in the throat or at the base of the filaments, for example in G. liliaceus and G. tristis.Particularly prominent ridges of papillae along the sutures of the tepals in the upper perianth tube in series Hebea of section Hebea do not appear to be the source of fragrance in this alliance of strongly scented species. Closing movements Flowers of most Gladiolus species close partially in the late afternoon.

This is accomplished by the movement of the tepals toward one another and the downward dipping of the dorsal tepal. Exceptions to this rule are species that are adapted for pollination by moths. These have pale-coloured flowers, often with brownish markings, and are often scented in the evenings. In G. longicollis, which is also thought to be pollinated by moths, the flowers close during the day and open only at sunset. Species with fairly complex flowers also may not close at all during the evening hours. These include G. dalenii and G.

ecklonii (section Ophiolyz.