Rhynchostylis gigantea (Lindl.) Ridl. - syn. Vanda gigantea Lindl.; Saccolabium giganteum Lindl. - Orchidaceae - foxtail orchid, Fuchsschwanz-Orchidee

Epiphytic orchid, native to Southeast Asia; stem erect, many leaved; leaves broadly lorate, 20-40 cm, fleshy, with amplexicaul sheaths at base; inflorescences 2-4, arching, 15-30cm long, many flowered; flowers sweetly fragrant, purplish red or white spotted with purplish red, or white (R. gigantea var. harrisonianum).

 nerol
nerol
(lemon floral)
citral.jpg
citral: geranial, neral
(citrus lemon)
 (E)-2,3-dihydrofarnesol
(E)-2,3-dihydrofarnesol
(floral green muguet)

Main constituents of the attractive citric scent of R.gigantea flowers were nerol (25.4%), methyl hexadecanoate (21.1%), (E,E)-farnesal (10.0%), (E)-beta ocimene (7.0%), (Z,E)-farnesal (6.9%), (E,E)-farnesol (5.1%), and hexyl benzoate (3.9%). Minor components were e.g. aldehydes like nonanal (0.97%), neral (0.57%), geranial (0.7%), dodecanal (0.94%), tetradecanal (1.7%); esters like neryl acetate (0.47%), isoamyl benzoate (0.15%), methyl tetradecanoate (0.85%), benzyl benzoate (1.4%), cis-3-hexenyl benzoate (0.37%), (Z,E)-farnesyl acetate (0.39%), and linalyl benzoate (0.26%); furthermore myrcene (1.8%), geraniol (1.7%) and eugenol (1.2%).
Main volatiles of the white flowers of R.gigantea var. harrisonianum were 2,3-dihydrofarnesol (34.3%), (E,E)-farnesal (17.3%), (Z,E)-farnesal (12.2%), nerol (8.6%), (E,E)-farnesol (4.5%), hexyl benzoate (2.8%), benzyl benzoate (2.1%), (Z,Z)-farnesol (1.9%), methyl cinnamate (1.6%), nonanal (1.4%), farnesene (1.2%), and (Z,E)-farnesyl acetate (1.1%).
[Julsrigival, Jakaphun, et al. „Determination of volatile constituents of Thai fragrant orchids by gas chromatography-mass spectrometry with solid-phase microextraction.“ J. Nat. Sci 12.1 (2013): 43-57]

saccolabium_giganteumvarillustre.jpg
Rhynchostylis gigantea (Lindl.) Ridley as Saccolabium giganteum Lindl.
Linden, J.J., Lindenia, Iconography of orchids (1885-1906) Lindenia vol.2 (1891) [Plates 289-312] t.83
http://www.plantillustrations.org/illustration.php?id_illustration=242375

rhynchostylisgigantea_ak.jpg
Rhynchostylis gigantea flowers CC BY-SA 3.0, Author: Andreas Kraska