Lilac
Syringa vulgaris (Oleaceae)
Common lilac is a native of the northern Balkan Peninsula. Around 1560, the German ambassador in Constantinople sent some specimens to Vienna, and the culture quickly spread to the rest of Europe. Like jasmine, lilac belongs to the olive family.
The beautiful fragrance of lilac flowers has recently been investigated by modern headspace techniques, revealing (E)-ocimene to be the major component, and the most characteristic components to be the furanoid terpene aldehyde 'lilac aldehyde' and the corresponding alcohol (four diastereoisomers each), benzyl methyl ether,
1,4-dimethoxybenzene (hydroquinone dimethyl ether) and indole. In fact the diffusive aura of lilacs in full bloom is highly influenced by the compound benzyl methyl ether. This simple but rare chemical has an intense fruity-etheral odor, reminiscent of the top note in ylang-ylang oil. Minor constituents of the lilac headspace are anisaldehyde, 8-oxolinalool, cinnamic alcohol and elemicin [8] [66] [67].
Etymology: Gr. syrinx, tube or flute, because of the hollow, marrow-filled branches; Lat. vulgaris, common.
P.S. As almost nothing is published on benzyl methyl ether, a note may be relevant concerning the small-scale synthesis of an olfactory pure quality of this odorant. Although the straightforward method would be from benzyl chloride and a surplus of methanolic sodium methoxide, this results in a product contaminated by an obnoxiously smelling impurity. Instead, benzyl alcohol should be methylated in methanol under mild conditions using an acidic catalyst and a water-removing agent (personal experiments).
P.P.S. The so-called syringaldehyde or syringic aldehyde, which is 4-hydroxy-3,5-dimethoxybenzaldehyde, is derived from the glucoside syringin, first isolated from lilac bark. Apparently it is of little importance in the headspace of lilacs.

citronellol, geraniol, geranyl acetate, farnesol, 2,3-dihydrofarnesol
benzyl alcohol, phenethyl alcohol, phenylacetonitrile (benzyl cyanide)
(Z)-3-hexen-1-ol, (Z)-3-hexen-1-yl acetate

Lily-of-the-valley
Convallaria majalis (Liliaceae)
Lily-of-the-valley is a flower of the forest-floor on poor and calcareous soil. In Scania in southern Sweden, for example, it is found in dense stands close to the bed-rock. Lily-of-the-valley is widely distributed in the northern hemisphere. The whole plant is poisonous.
The intense and elegant fragrance of the flowers may be described as "delicately floral, with a distinct touch of greenness, surrounded by fresh, rosy-lemony nuances" (Kraft et al.) [43].
In a study on the headspace of lily-of-the-valley flowers using GC-MS and GC-sniffing/GC-olfactometry techniques, Brumke, Ritter and Schmaus from the company Dragoco (today Symrise, Germany) identified some 23 compounds contributing to the lily-of-the-valley fragrance, among these several newly detected trace constituents [210]. The odorants could be divided into floral-rosy-citrusy notes: citronellol (9.6 %), geraniol (8.4%), nerol (1.3 %), citronellyl acetate (1.1 %), geranyl acetate (3.3 %), geranial + benzyl acetate (0.96 %), neral (0.02 %), benzyl acohol (35 %), phenethyl alcohol (0.78 %), phenylacetonitrile (3.0 %), farnesol (1.9 %) and 2,3-dihydrofarnesol (0.88 %), green-grassy notes: (Z)-3-hexen-1-ol (11 %), (Z)-3-hexenyl acetate (7.8 %), (Z)-3-hexenal (trace) and (E)-2-hexenal
(0.18 %), green pea and galbanum-like notes: 2-isopropyl-3-methoxypyrazine (trace) and 2-isobutyl-3-methoxypyrazine (trace), fatty, waxy, aldehydic notes: octanal (0.15 %), nonanal (0.1 %), decanal (0.07 %) and fruity, raspberry notes: beta-ionone (trace). In another study of lily-of-the-valley, phenylacetaldehyde oxime was identified [66].
Etymologi: Lat. convallis, valley; Lat. majalis, belonging to May or blooming in May. In France lily-of-the-valley is called muguet.

Lindenblossom
Tilia cordata (Tiliaceae) Litle-leaf Linden
Tilia platyphyllos (Tiliaceae) Large-leaf Linden
Tilia europaea (Tiliaceae) Linden
In Denmark, the lindens of the cities are mostly T. europaea, a crossing between T. cordata and T. platyphyllos. In southern Europe they are predominantly T. platyphyllos. However, the separate species may be hard to distinguish.
The airy, honey-green fragrance from the large, blooming trees brings a magic refreshment to the warm summer-breeze. Bees and other insects love the nectar of the lindenblossoms, placed in the sepals of the hanging flowers, protected from rain. The dried flowers make a delightful tea.
The chemistry of indenblossom fragrance is extremely complex. Naef et al. recently made an interesting study of the change in volatiles taking place by going from lindenflower (T. cordata) nectar via bee-stomach to ripe lindenflower honey. The nectar volatiles were found to be composed of fatty acid degradation products, e.g. nonanal and decanal, isoprenoids like megastigmene-dione, a complex mixture of monoterpenoids, among them the so-called 'linden ether' (2,4,5,7a-tetrahydro-3,6-dimethylbenzofuran) and, tentatively identified as the major component,
8-hydroxy-p-mentha-1,3-dien-7-al. Moreover, a number of phenylpropanoids were identified, among them
3-(4-methoxyphenyl)-propanal and the corresponding alcohol [27].

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