Asclepias tuberosa

Asclepias tuberosa

Asclepias tuberosa, also called Knollige Milkweed or Orange Milkweed, is a species of the genus milkweed ( Asclepias ) in the subfamily Asclepiadoideae within the family of the dogbane family ( Apocynaceae ). The wide range extends from Alaska to northern Mexico.

• 4.1 Medical Importance

• 6.1 Literature
• 6.2 Notes and references

Description

Vegetative characteristics

Asclepias tuberosa grows as a perennial herbaceous plant, reaching heights of growth of up to about 90 cm. The milky sap is clear. It forms a deep reaching tap root out every year in the spring grow to about a 100 strong stems. The only on the inflorescence branching stems are covered with thin soft or stiff hairs ( trichomes ).

The irregular, usually alternate on the stem arranged leaves have short, 1-5 mm long stalks. The thin solid and occasionally ruffled leaf blade is at a length of 3 to 11 cm and a width of 0.3 to 3.0 cm narrow to broad lanceolate sharpened or rounded end. Especially the lower leaf surface is covered with thin hairs.

Generative features

The flowering period extends from May to July. The inflorescence bears few to many, terminal to subterminal, little - to Vielblütige, umbel- shaped Cymoide. The corolla has a diameter of up to 1 cm, depending on how strong the corolla lobes are bent. The 7-8 mm long corolla lobes are strongly recurved and vary in color from yellowish, usually orange to red. The pedunculated Gynostegium is usually orange, rarely yellow. The stem has a length of about 2 mm long and have a diameter of about 1.5 mm. The corona lobes are erect oblong- lanceolate, hood -shaped and 4-5 mm long. The horn-shaped secondary extension is longer than the tip and bends one over the Gripfelkopf. The stylus head is cylindrical and measures approximately 2 mm in height and 2 mm in diameter.

The upright on a short stalk follicles are relatively long and slender with a length of 8 to 15 cm and a diameter of 1.0 to 1.5 cm. Their surface is covered with warts and bald. The at a length and width 5-7 mm wide, ovate, flat seeds have a 3 to 4 cm long, white hair.

The basic chromosome number is n = 11

Ecology

Pollination is usually by large bees and wasps, less often by butterflies. Asclepias tuberosa is an important food plant for the caterpillars of the monarch butterfly (Danaus plexippus).

Occurrence

Asclepias tuberosa is found in almost all continental states of the USA, with the exception of Washington, Oregon, Idaho, Nebraska, Montana, North Dakota and Alaska and southeastern Canada ( Quebec and Ontario) and northern Mexico.

Asclepias tuberosa is a common wild plant along roads and other human -influenced habitats. It prefers rocky, relatively dry soils and sunny locations.

Use

Due to their yellow to bright orange-red inflorescences Asclepias tuberosa is used as an ornamental plant. In Central Europe it needs but usually a slight winter protection.

Medical importance

In the 19th century plant parts were used for lung problems such as asthma and bronchitis. Asclepias tuberosa is still used in homeopathy as remedy.

System

Asclepias tuberosa is the kind of Woodson (1954 ) divided into four subspecies:

• Asclepias tuberosa subsp. tuberosa: The leaves are ovate to lance-shaped and typically wedge-shaped at the base, the margins are usually smooth. Distribution: New Hampshire to northern Florida ( there in the subsp rolfsii temporarily. ), West to the Alleghenies ( there into the interior subsp temporarily. )
• Asclepias tuberosa subsp. rolfsii: The leaves typically lanceolate with ruffled edges. Florida to Georgia ( there she goes in the subsp. Tuberosa above ) and westward along the coast of the Gulf of Mexico to Alabama ( there she goes in the SSPP. Tuberosa interior and over )
• Asclepias tuberosa subsp. interior: The leaves are typically heart-shaped. Distribution: Ozark Plateau eastwards to the Alleghenies ( there in the subsp tuberosa temporarily. ), Southward to the level of the Gulf of Mexico ( there in the subsp rolfsii temporarily. ), And in an arc west and north from Texas to in the north from Michigan extend ( there she goes in the subsp. terminalis on ).
• Asclepias tuberosa subsp. terminalis: The leaves lanceolate, ovate, oblong to elliptic with smooth edges. At the base they are typically blunted or truncated to heart-shaped. This subspecies occurs on the western edge of the distribution area of the species before, Tamaulipas northwestward into southern Utah, and eastward to Colorado, South Dakota, southern Minnesota, Wisconsin, and in the north from Michigan (where in an arc eastward and southward in subsp. interior temporarily ).

Swell