matthiola_incana_l.

Matthiola incana (L.) W.T.Aiton - syn. Cheiranthus incanus L. - Brassicaceae
common stock, Brompton stock, tenweeks stock, hoary stock, gilly-flower, (Garten-) Levkoje

Annual or biennial to perennial herb, up to 80cm tall, native to the Mediterranean, naturalized and cultivated elsewhere; leaves oblanceolate, entire;, up to 16 cmlong; racemes 15-30-flowered, up to 30 cm long in fruit, flowers 2-4cm across, mauve or violet, fragrant in the evening (as also Matthiola longipetala); fruit (siliquae) 10-15cm long, 2.5-4mm broad; seeds 2mm in dia., brown, winged.
http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=200009612

„The double-flowered form is caused by a recessive gene variant (allele) in the homozygous condition. Therefore,… heterozygous single-flowered stocks should produce one quarter doubles in their offspring… Selection over the centuries has greatly improved these ratios, resulting in the so-called „ever-sporting“ stock… In these varieties, the singleness allele is closely linked to a pollen-lethal gene… many modern strains produce doubles in even higher proportions: 60% or even 80%.“
http://en.wikipedia.org/wiki/Matthiola_incana

The flowers emit a pleasant floral, clove-like odor which is attributed to constituents like 2-phenylethanol, anol (4-propenylphenol), eugenol, methyl eugenol, isoeugenol, and related compounds. Vaccum headspace concentrates contain nitriles and isothiocyanates as artifacts.
[Surburg et al., Volatile compounds from Flowers, in: Teranishi, R.;Buttery, R. G.;Sugisawa, H. Bioactive volatile compounds from plants. (Book) 1993, 176]

From the volatile compounds isolated from M.incana flower oil (SDE), the main ones were β-pinene(13.2%), 3-carene(10.1%),(-)-isoledene(4.8%), β-bourbonene (4.5%), spathulenol (3.3%) and β-cadinene(3.2%).
[Analysis of chemical composition of volatile oil from flowers of Matthiola incana L. and its evaluation for cigarette flavoring., Gao, Ze-rui, et al., Chemical Research and Application Vol.6, 2013, 30]

The flower extract (n-hexan) consisted mainly of fatty acids (tetradecanoic acid 18%, hexadecanoic acid 12%) and alkanes (C14-C20). Monoterpenes detected were limonene, α-terpineol, geraniol, sabinene, and myrcene.
[Evaluation of antioxidant activity, cytotoxic studies and GC-MS profiling of matthiola incana (stock flower)., Rasool, Nasir, et al., Legume Research-An International Journal Vol.36(1), 2013, 21-32]

Headspace analysis (SPME; GC-MS DB-wax) of the flowers showed eugenol (33.71%), methyleugenol (23.07%), limonene (11.34%), anethol (8.03%), phenylethanol (4.02%), phenylacetaldehyde (1.34%), isoeugenol (0.89%), benzyl acetate (0.63%), methyl salicylate (0.18%), and anisaldehyde (0.09%) as main components.
[Kang S, Yun BI, European patent EP 3 446 676 A1 (2019)] European publication server EP3446676

Weinmann,J.W., Phytanthoza iconographia, Vol.3, t.643, (1742)
http://plantgenera.org/species.php?id_species=647954