Asclepias purpurascens
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Asclepias purpurascens |
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| Asclepias purpurascens | ||||||||||||
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Asclepias purpurascens is a species of silk plants ( Asclepias ) from the subfamily of the silk plants (Asclepiadoideae). It is native to North America.
description
Vegetative characteristics
Asclepias purpurascens is a perennial herbaceous plant that reaches heights of 40 to 100 cm. The sturdy stems are initially weak and hairy when young, later bald. The milky juice is whitish. The opposite leaves on the stem have a 0.5 to 2.5 cm long stem. The leaf blade is 6 to 18 cm long and 3 to 10 cm wide - elliptical to ovate - elongated or lanceolate with a blunt or pointed end. The base of the blade is angular or broadly rounded and ends very briefly in a wedge shape in the petiole. They are dark green and glabrous on top, lighter green and fluffy on the underside.
Generative characteristics
The golden inflorescences are usually terminal and solitary or in pairs, rarely a few additional inflorescences also form in the uppermost leaf axils; they contain several to many flowers. The slender inflorescence shafts are about 1.5 to 9 cm long and finely tomentose. The flower stalks, which are also quite thin and finely tomentose, are 2.0 to 3.5 cm long. The relatively large and striking purple flowers are hermaphroditic and five-fold. They produce a relatively large amount of nectar, which contains simple sugars. The five sepals are ovate-lanceolate, 3 to 4 mm long and finely tomentose. The tips of the five petals are bent back and 7 to 10 mm long. The gynostegium has a very short stem that is conical, 1.5 to 2 mm long and 2.5 to 3 mm wide. The corolla lobes are elongated-elliptical and pointed with a length of 6 to 7 mm. The horn-shaped extension on each tip is half-fitting, sickle-shaped and sharply curved and much shorter than the tip. The stylus head is tapered and cut off at the top. It measures 2 mm in length and 3 mm in width. In the New England states, Asclepias purpurascens blooms in June and July.
The follicles appear in late summer. The fruits stand upright on stems that are sharply bent downwards. They are spindle-shaped with a length of 10 to 16 cm and a diameter of 1 to 2 cm. On the outside, they are essentially hairy or hairy, slightly finely tomentose. The oval seeds are 5 to 6 mm long, with a white head of hair 3.5 to 4.5 cm in length.
Occurrence
Asclepias purpurascens is native to North America (USA and Canada). It occurs in Canada in Ontario, in the USA in the states, Arkansas, Connecticut, Delaware, District of Columbia, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi , Missouri, Nebraska, New Hampshire, New York, New Jersey, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Tennessee, Texas, Virginia, West Virginia and Wisconsin. It grows there in bushland, light forests, prairies and fields, also in the cultural area and along roads and railways.
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literature
- EG Choberka, MR Penskar and PJ Higman: Special plant abstract for Asclepias purpurascens (purple milkweed). 2 pp., Michigan Natural Features Inventory, Lansing, MI 2004 (updated 2009). PDF.
- Elizabeth J. Farnsworth and Mario J. DiGregorio: Asclepias purpurascens L. Purple milkweed. 36 pp., New England Wild Flower Society, Framingham, MA, 2001 PDF.
- Carl von Linné: Species Plantarum . Vol. 2, 1st edition, Lars Salvius, Stockholm 1753 (description of A. purpurascens on pp. 214/5) online at botanicus.org.
- Robert E. Woodson, Jr .: The North American Species of Asclepias L. Annals of the Missouri Botanical Garden, 41 (1): 1-211, St. Louis, Mo., 1954 URL (description by A. purpurascens on p. 118–120)
