Asclepias erosa
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Asclepias erosa |
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Asclepias erosa is a species of silk plants ( Asclepias ) from the subfamily of the silk plants (Asclepiadoideae). The specific epithet erosa refers to the serrated leaf margins. Asclepias erosa is one of the largest American silk plants.
description
Vegetative characteristics
Asclepias erosa is a massive, perennial herbaceous plant that reaches heights of 1 to 2 meters. The 8 to 20 stems are relatively thick, simple or rarely branched and more or less woody at their base. Fresh stems are finely haired, later they become bald.
The against-constantly arranged on the stem leaves are short-stalked or sitting. The simple leaf blade is broadly oval, occasionally elongated oval or elliptical with a pointed and short end. The leaf base is broadly heart-shaped and amplexicaul, i. H. encompassing the stem. The leaves are 6 to 24 cm long and 2.5 to 11 cm wide. They are tightly skinned, occasionally also subsucculent. The leaf margin is finely jagged. With fresh leaves, the surface is covered with white, fine hairs; as they age, they become bald and light green.
Generative characteristics
The inflorescences, which are usually single, rarely paired, in some of the uppermost leaf axils contain many flowers. The 2 to 12 centimeters long inflorescence shafts are finely haired with white hair. The 1.2 to 3.5 cm long flower stalks are also finely hairy with white hair.
The relatively large flowers are hermaphrodite, radial symmetry and five-fold with a double flower envelope . The five sepals are lanceolate with a length of 4 to 6 mm. The five light yellowish-green petals are 9 to 10 mm long. The whitish-green or cream-colored gynostegium has a short, conical stem that is about 2 mm high and about 3 mm in diameter. The corolla lobes are very broadly oval, broadly truncated at the tip and about 4 mm long. The horn-shaped secondary process lies tightly over the entire route. It is sickle-shaped and about as long as the staminal corolla lobes. The stylus head is conical, cut off at the top, and approximately 3 mm long and 4 mm wide. Flowers appear from April to October.
The upright upwardly curved stems follicles are having a length of 5 to 7 cm and a width of 2 to 3 cm wide-spindle-shaped and shortly pointed above. Their surface is smooth. The seeds are very broad-oval with a width of 13 mm and have a 1.5 mm long, light brown head of hair.
Occurrence
Asclepias erosa occurs in the US states of Arizona , California , Nevada and Utah and in the Mexican state of Baja California . It thrives at altitudes between about 50 to about 1500 meters. It grows in dry ravines, erosion channels and canyons, where rain falls only irregularly and rarely. It is also found along highways and railroad lines.
swell
literature
- Robert E. Woodson, Jr .: The North American Species of Asclepias L. , In: Annals of the Missouri Botanical Garden , Volume 41 (1), St. Louis Mo., 1954, pp. 1-211. Url
- Eric Sundell: Asclepiadaceae Milkweed Family. , In: Journal of the Arizona-Nevada Academy of Science , 27 (2), 1993, pp. 169-187. PDF
- Janice Emily Bowers : Flowers and Shrubs of the Mojave Desert. 142 pp., Tucson, AZ, Southwest Parks and Monuments Association, 1999 Online at GoogleBooks .
