Resedaceae (Mignonette Family)

Reseda lutea is visited by the hymenopteran sawflies (Symphyta), solitary wasps (Sphecidae) and parasitoid wasps(Ichneumonidae) which are drawn to feed on the partially concealed nectar. Similarly, Weld is known to be visited by wasps (Vespidae). Both plants are also visited by the small bee Prosopis. These insects are presumably attracted by the mignonette's scent. Click image for full size.

Above and below: Wild Mignonette (Reseda lutea)

Above: a Wild Mignonette (Reseda lutea) beginning to form fruit. Below: close-up of fruit, each formed by 3 fused carpels.

The Resedaceae or Mignonette family contains at least 8 genera and about 100 species. The genus Reseda contains about 55 species. In Reseda the flowers are arranged on a raceme at the end of a branch, which is like a spike except that each flower is borne on a distinct stalk or pedicel. The Resedaceae occur in
northern and southern temperate and subtropical zones. Reseda occurs in the Mediterranean region and parts of Africa and W. Asia, but has naturalised in regions of the Southern Hemisphere, for example in Australia.

Wild Mignonette (Reseda lutea)

Each flower of Reseda lutea has 6 free sepals and 6 free yellowish-green petals (4 to 6 or occasionally 8 is the norm for the family) and is zygomorphic (with bilateral symmetry) since the upper, lateral and lower petals all differ slightly in form. The structure of the flowers is hard to discern at first glance, but a close examination will show the structure. The number of stamens is variable (indeterminate) at about 12 to 20. There are three carpels forming a compound ovary which is open at the top, with three distinct apices or lobes, each apex bearing one stigma (there is no style). This compound ovary has one chamber containing three double rows of ovules which may develop into seeds. The 2 upper petals are the largest and each divided into 3 lobes, the 2 lower petals are entire (not divided into lobes) and each of the pair of lateral petals is divided into 2 or 3 lobes. The flowers are hypogynous (sepals, petals and stamens are attached at the base of the ovary, in other words the ovary is superior, i.e. above the other flower parts on the receptacle).

Wild Mignonette flowers from later late Spring to late Summer (May to August). A large amount of nectar is produced by a nectar-secreting disc upon which the stamens are mounted. Wild Mignonette is good for honey production.

Above: the petal forms in Reseda lutea (based on Abdallah and De Wit, 1978). Dotted lines indicate serrulate (finely serrated) margins.

The fruit is a capsule about 1 cm long, open at the top with three lobes, reflecting the three carpels from which it develops. It contains a single seed-containing cavity (the ovary has one locule with many ovules within it) and the seeds are shiny black, kidney shaped and about 2 mm long.

Reseda lutea is biennial to perennial and the stem and root develop consoderable secondary xylem. Myrosin cells are scattered throughout the stem cortex, the leaf mesophyll and the cortex and pith of the roots. Myrosin cells contain myrosinase, an enzyme catalyzing the synthesis of thiols from glucosinolates (chemicals consisting of molecules of glucose joined to a sulfur and nitrogen-containing organic group by a glycosidic link). The hydrolysis (reaction with water which splits a molecule) of the glucosinolates generates glucose and thiol. Thiols give foods such as mustard, horseradish and cabbage their hot, tangy flavors when crushed. This is thought to be a defense against herbivores: damage to the tissues causes synthesis of the thiols to deter the predator. In moderation, however, humans like to eat such plants and the leaves of Wild Mignonette have been eaten in salads. 

Click images for full size.

A yellow dye can be extracted from the whole plant, prior to fruiting, especially the flowers and young shoots and this is used for dying Turkish rugs. The plant has also been used as a sedative, diuretic and sudorific (sweat-inducing) agent.

The leaves of Wild Mignonette are typically deeply divided into lobes.

The 12 to 20 stamens, longer than the petals, hang down from each flower. Each flower also produces 3 (4) sessile (stalkless) stigmas. Click images for full size.

The stem of Wild Mignonette usually puts out several ascending and flexuous branches. The main stem may reach 30 inches (75 cm) in height. The flowers are arranged in dense conical racemes (flower spikes). The fruit are arranged more laxly (i.e. more separated along the raceme). The plant is found in waste places and grassland and prefers calcareous soils. Click image for full size.

Weld (Reseda luteola)

Another example of the Resedaceae, also used to extract a yellow dye for dyeing Turkish Rugs (and formerly used to dye silk, cotton and linen), is the Weld (Wild Dyer's weed), Reseda luteola. The whole plant is used to prepare the dye, but the dye is thought to be most abundant in the seeds. Weld is a biennial similar to Reseda lutea in some ways, but instantly recognisable due to its pointed strap-like leaves and generally larger size, reaching 1.5 m in height (compared to 0.75 m for Reseda lutea). It's flowers are borne on longer racemes which appear narrow due to the short flower stalks.

The flowers of Weld have 4 sepals and 4 petals (3-4, occasionally 5) (compared to 6 and 6 for R. lutea). The upper petal is partially divided into 3-9 segments; the two lateral petals each have 3 segments and when 4 or 5 petals are present, then these lower petals are linear and undivided (entire) with one additional small lobe. There are 3 stigmas and 20 to 25 stamens per flower. The short flower stalks give the racemes a narrower, more compact and spike-like appearance. The upper petals is multi-lobed, the lateral and lower petals are trilobed.

The ovary and developing fruit have the three part structure with the central opening or depression characteristic of Reseda.

The leaves of Weld are lanceolate (pointed and blade-shaped) and entire (they are not subdivided into lobes or leaflets).

Weld grows in waste places and especially, as here, on calcareous soils. It produces a long, tapering tap-root.

The nodding flower spikes of Weld follow the Sun across the sky.

Above and below: the fruit consist of 3 united carpels that open at the apex (and are separate to about one-third the way down) before the seeds are ripe and shed the small dark-brown and shiny seeds.

Further Reading

Abdallah, M.S. and H.C.D. De Wit, 1978. The Resedaceae: a taxonomic revision of the family.

Dogan, Y. 2001. A Study on the Autecology of Reseda lutea L. (Resedaceae) Distributed in Western Anatolia. Turk J Bot 25: 137-148.

Dogan, Y., H. Mert and K. Akcan, 2008. Anatomical studies of Reseda lutea (Resedaceae). Phytologia
Balcanica 14: 91 –95.

Radulovic, N.S., D.B. Zlatkovic, T. Ilic-Tomic, L. Senerovic and J. Nikodinovic-Runic, 2014. Cytotoxic effect of Reseda lutea L.: A case of forgotten remedy. Journal of Ethnopharmacology 153: 125–132.

Article created: 16/9/17
Article updated: 3/6/2018, 24/6/2019, 1 Aug 2020, 15 Aug 2020