Asclepias speciosa Torr. - Apocynaceae - showy milkweed, Schöne Seidenpflanze
Perennial herb, up to 60-100cm high, native to western and central North America.
„The eye-catching furry pale pink to pinkish-purple flowers are arranged in thick umbels… Asclepias speciosa is a specific Monarch butterfly food and habitat plant.“ http://en.wikipedia.org/wiki/Asclepias_speciosa
„Asclepias speciosa occurs on mountain meadows, open woods and along rivers, and in cultivated land. It grows widely on roadsides and along the railway lines. Asclepias speciosa grows at altitudes 1500-2600 meters.“ http://de.wikipedia.org/wiki/Asclepias_speciosa
„Six compounds comprised >90% of the milkweed floral components in the pentane extract: (E)-β-ocimene, benzaldehyde, nonanal, benzyl alcohol, phenylacetaldehyde, and (E)-2-nonenal. The volatile profile collected by DVB/CAR/PDMS SPME directly from fresh flowers was dominated by three of these compounds, (E)-β-ocimene, benzaldehyde, and phenylacetaldehyde (>75% of the total), but there were also substantial differences compared to the extract. Most notably, (E,Z)- and (E,E)-alloocimene were collected from the flower headspace, but were almost completely absent from the extract, while nonanal, a major constituent of flower extract, was missing in the headspace. These disparities can be partly explained by variation in volatility among the components, but may also reflect actual differences between the chemical composition in flower tissue and what is released.“
[Plant Semiochemicals as Mosquito Attractants. Dissertation by Philip E. Otienoburu. The Ohio State University 2011, 59] https://etd.ohiolink.edu/!etd.send_file?accession=osu1313605670&disposition=attachment