Asclepias vestita
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| Hook. & Arn. |
Asclepias vestita is a species of silk plants ( Asclepias ) from the subfamily of the silk plants (Asclepiadoideae). It is found in the central and southern parts of California .
features
Appearance, root, stem and leaf
Asclepias vestita is a perennial , herbaceous plant that sprouts from the "root stock" every year. The tufted ascending or more or less recumbent, strong shoot axes have upright shoot tips are laterally flattened and / or provided with more or less pronounced edges. The unbranched to rarely branched (already at the base) shoot axes are 20 to 70 cm long (up to 1 m). The fresh shoot axes are densely hairy and can later become bald.
The opposite arranged leaves are divided into a petiole and a leaf blade. The leaf stalk is relatively short with a length of 0.4 to 1 cm. The simple, tight-skinned, occasionally even somewhat succulent leaf blade is 4 to 14 cm long and 2 to 5 cm wide and is ovoid to broadly lanceolate with a broadly rounded and heart-shaped blade base and a pointed outer end. Fresh leaves are noticeably hairy, especially on the underside of the leaf; with increasing age they more or less bald.
Inflorescence and flower
The flowering period extends from April to July. The inflorescences sitting individually and terminally, or two to three laterally on the uppermost nodes , contain up to ten flowers. The slender flower stalks are 2 to 3 cm long and are covered with fine, white downy hairs.
The hermaphrodite flowers are zygomorphic and five-fold with a double flower envelope . The five fine downy hairy sepals are lanceolate with a length of 4 to 5 mm. The corolla is medium in size. The 7 to 8 mm long petals are spread out in the shape of a wheel, yellowish-white and tinted more or less purple. The short-stalked corolla is white to cream-colored. The stem is broad-inverted-conical with a length of about 1 mm and a diameter of about 2 mm wide. The 2 to 3 mm long tips of the secondary crown are triangular to obovate in outline and flattened at the outer end. The secondary process on the inside of the tip is curved sickle-shaped and lies on the inside of the respective tip; it is about as long as the tip. The stylus head is flattened, conical, about 2 mm long and 3 mm wide.
Fruit and seed
The follicles stand upright on curved stems. The follicles are 5 to 8 cm long and about 3 cm wide, fusiform and short-pointed. The smooth surface is densely covered with short hairs like a mat, but it can also be almost bare. The seeds are broad-elliptical with a length of about 1 cm. The light brown head of hair is up to 2.5 cm long.
Occurrence
The area of Asclepias vestita is limited to the central and southern parts of California . It grows there at altitudes of 50 to 1350 meters in dry plains, bushland, grassland, but also in sparse forests.
Systematics and phylogeny
The first description of Asclepias vestita was made in 1844 by William Jackson Hooker and George Arnott Walker .
Two subspecies are currently accepted:
- Asclepias vestita subsp. vestita : It is characterized by a strong stem axis, slightly larger leaves (than the subspecies parishii ), terminal, but also lateral inflorescences. The yellowish-white corolla shows only a little purple tint. It blooms from April to July. Distribution: central part of California in the California Longitudinal Valley and central-western California.
- Asclepias vestita subsp. parishii (Jepson) Woodson : The shoot axes are slimmer, leaves narrower and smaller. Usually only a single, terminal inflorescence per stem axis is formed. The yellowish-white corolla is usually strongly tinged purple. It blooms from April to May. Distribution: Southern California in central-western California, the Transverse Ranges and the Mojave Desert .
The two subspecies are not as well defined or sharply demarcated as other subspecies within the genus Asclepias . However, there is a very clear geographical distribution without major overlaps.
According to the molecular genetic analysis of various Asclepias species from North America, Asclepias vestita is the sister species of Asclepias californica .
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 (pp. 148/9)
- California Pollinator Plants Native Milkweeds (Asclepias spp.) The Xerces Society of Invertebrate Conservation 2011 PDF
- Lester Rowntree: Hardy Californians: A Woman's Life With Native Plants. 308 pp., Berkeley, University of California, 2006. ISBN 978-0-520-25051-2 Asclepias vestita on p. 179 in the Google book search
- Abrams Le Roy, Roxana Stinchfield Ferris: An illustrated Flora of the Pacific States Washington, Oregon and California. Geraniaceae to Scropulariceae Geraniums to figworts. California Univ. Press 1951 online at www.biodiversitylibrary.org
- Asa Gray: Synoptical flora of North America. vol. II, part I Gamopetale after Compositae., 1-402, Washington, DC, 1878 Online at www.biodiversitylibrary.org (p. 94)
Individual evidence
- ↑ a b c d e Thomas J. Rosatti & Carol A. Hoffman, 2013: Jepson eFlora.
- ↑ Bring Back The Monarchs
- ^ William Jackson Hooker, GA Walker Arnott: The botany of Captain Beechey's voyage, comprising an acount of the plants collected by Messrs. Lay and Collie, and other officers of the expedition, during the voyage to the Pacific and Behring's Strait, performed in His Majesty's ship Blossom, under the command of Captain FW Beechey ... in the years 1825, 26, 27, and 28. London, HG Bohn, 1841 Online at www.biodiversitylibrary.org (p. 363).
- ^ Willis Linn Jepson: Manual of the Flowering Plants of California. University of California Press, Berkeley, 1925 Online at Google Books (p. 772)
- ↑ Mark Fishbein, David Chuba, Chris Ellison, Roberta J. Mason-Gamer, Steven P. Lynch: Phylogenetic Relationships of Asclepias (Apocynaceae) Inferred from Non-coding Chloroplast DNA Sequences. In: Systematic Botany , Volume 36, No. 4, 2011, pp. 1008-1023 doi : 10.1600 / 036364411X605010