Botanical description of the plant
L ‘ Artemisia annua (Artemisia annua L. – Asteraceae family), also known as “annual wormwood” is a small, highly aromatic herb. It has green and glabrous leaves and can reach a maximum height of 200 cm. The root is taproot, with lateral filaments.
Stem erect, branchy from the base or sometimes monocaule, cylindrical, streaked and reddened in the median and terminal part (the whole plant with age).
Tomentose leaves on the underside, deep green on the top which also has glandular spots; 2 – 3 pinnatosette with triangular outline 3 – 5 (10) x 2 – 4 cm and slightly revolute edges, leaf rachis strictly winged, the lobes are narrow and toothed, petiole 1 -2 cm; the leaves placed in the median and apical part are 1 – 2 pinnate matches.
Inflorescence formed by a terminal and leafy panicle of hanging flower heads 15 – 20 cm; flower heads 1.5 – 2.5 mm in diameter, lanceolate imbricated bracts, straw-colored and with hyaline green central rib, not exceeding the corolla, very short peduncle.
Flowers, pentamers, hermaphrodites composed of an actinomorphic tubular corolla of 1.5 mm, straw or dark yellow in color, simpetala, five-lobed margin in the internal hermaphrodite flowers and bilobed in the external female ones.
Stamens 5; anthers welded together, deeply bifid stigma; inferior ovary, bicarpal and unilocular.
The fruit is an elliptical-ovoid achene without pappus. Numerous and very small seeds.
It is native to the province of Hunan in China , where it grows spontaneously in the woods, in humid environments, slopes, river banks, ruins, sandy or gravelly soils from 0 to 500 m asl.
In Italy it is quite rare and mainly present in the Alps , even if in a discontinuous way.
Outside Italy, still in the Alps, it is found in France (departments of Isère and Haute-Savoie), in Switzerland it is in the Canton of Ticino, while in Austria it is present in the Länder of Vorarlberg, North Tyrol and Carinthia. On the other European reliefs it is found in the Jura Massif, the Balkan Mountains and the Carpathians.