Asclepias longifolia
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Asclepias longifolia |
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Asclepias longifolia is a species of silk plants ( Asclepias ) from the subfamily of the silk plants (Asclepiadoideae).
features
Vegetative characteristics
Asclepias longifolia is a perennial , herbaceous , upright plant with a bulbous rhizome. The annual shoots are slender and unbranched, 20 to 70 cm high and have fine, downy hairs. They die off completely in autumn and sprout again from the rootstock in spring. The irregularly arranged, closely spaced leaves are sessile to very short stalked. The leaf blades are linear-lanceolate and pointed at the outer end, at the base they are gradually slimmer. They are 6 to 18 cm long, 2 to 10 mm wide and finely downy hairy to almost bald.
Inflorescence and flowers
The single, stalked inflorescences are terminal and arise from the uppermost nodes . They have few or more flowers and are hemispherical with rather loosely arranged flowers. The slender stems are 2 to 6 cm long and have fine, downy hairs. The flowers are rather small with very slender, 1.5 to 2 cm long, finely hairy pedicels. The sepals are lanceolate and about 2 mm long, and also finely hairy. The corolla is wheel-shaped with strongly curved back petals . These are about 5 mm long, pale greenish-white with a purple tint, especially on the outside. The single-row, greenish-white corolla is short-stalked and tinted a little purple, especially below. The stem is 1.5mm long and 1mm thick. The tips of the secondary crown are deeply sack-shaped, obverse-shaped in outline and about 2 mm long. There is no horn-shaped secondary process. The tips are much shorter than the stylus head . This is about 1.5 mm high and just as wide.
Fruits and seeds
The paired, finely downy hairy follicles stand upright on U-shaped curved stems. They are narrow-spindle-shaped and 8 to 12 cm long and about 1 cm thick. The seeds are broadly elliptical, about 1 cm long with a white head of hair about 3.5 cm long.
Geographical distribution and ecology
The range of the species extends over the coastal plains of the southeastern USA ( Alabama , Delaware , Florida , Georgia , Louisiana , Mississippi , North Carolina , South Carolina , Texas and Virginia ). It grows there in swamps and low pine forests and blooms from April to July.
Taxonomy and systematics
The taxon was first described in 1803 by André Michaux in his Flora boreali-americana . Younger synonyms are:
- Anthanotis procumbens Raf.
- Acerates delticola Sm.
Currently the species is divided into two subspecies (or varieties):
- Asclepias longifolia ssp. longifolia or var. longifolia
- Asclepias longifolia ssp. hirtella (Pennell) J. Farmer & CRBell or Asclepias longifolia var. hirtella (Pennell) BLTurner
The subspecies (or variety) hirtella differs in the splayed downy hairs on the pedicels, while in the subspecies (or variety) longifolia the downy hairs are pressed upwards on the peduncle. It is also limited in distribution to Louisiana and Texas. The distribution area of the subspecies (or variety) longifolia within the range of the species just extends into the easternmost Louisiana; it does not occur in Texas.
supporting documents
literature
- Robert E. Woodson, Jr .: The North American Species of Asclepias L. In: Annals of the Missouri Botanical Garden , Vol. 41, No. 1, 1954, pp. 1-211, St. Louis, Mo. URL
- Miles F. Johnson: Studies in the Flora of Virginia: Asclepiadaceae. In: Castanea , Vol. 48, No. 4, 1983, pp. 259-271 URL
Individual evidence
- ^ André (Andreas) Michaux: Flora boreali-americana, sistens caracteres plantarum quas in America septentrionali collegit et detexit. Parisiis et Argentorati, apud fratres Levrault, anno XI - 1803. Online at www.biodiversitylibrary.org (p. 116/7)
- ^ Constantine S. Rafinesque-Schmaltz : Florula Ludoviciana, or, a Flora of the State of Louisiana. Translated, Revised, and Improved, from the French of CC Robin. 178 p., New York, 1817 Online at Google Books (p. 51/2, p. 149)
- ^ John K. Small: Manual of the southeastern flora. 1554 S., New York, 1933 (p. 1067).
- ↑ Rafael Govaerts (ed.): World Checklist of Selected Plant Families (in review): Asclepias. Published in: The Plant List. A working list of all plant species. Royal Botanic Gardens Kew, Missouri Botanical Garden, accessed May 16, 2013.
- ↑ Billie L. Turner: Taxonomy of Asclepias hirtella and A. longifolia (Apocynaceae). In: Phytologia , Vol. 91, No. 2, 2009, pp. 308-311 online
