Asclepias erosa

Asclepias erosa

Asclepias erosa is a plant of the genus milkweed ( Asclepias ) from the subfamily of milkweed plants ( Asclepiadoideae ). The specific epithet refers to the erosa serrated leaf margins. Asclepias erosa is one of the largest American milkweed plants.

• 3.1 Literature

Description

Vegetative characteristics

Asclepias erosa is a massive, perennial herbaceous plant that reaches the stature heights of 1 to 2 meters. The 8 to 20 stems are relatively thick, simple or rarely branched and woody, more or less at their base. Fresh stems are finely hairy, later they are bald.

The constantly against the stem arranged leaves are short -stalked or sessile. The simple leaf blade is broad - oval, sometimes elongated oval or elliptical and recently sharpened end. The leaf base is broad - cordate and amplexicaul, ie the stem comprehensively. The leaves are 6-24 cm long and 2.5 to 11 cm wide. They are firmly membranous, sometimes subsukkulent. The leaf margin is finely serrated. In fresh leaves, the surface is covered with fine white hairs; with increasing age they are bald and pale green.

Generative features

The usually solitary, rarely paired, standing in some of the uppermost leaf axils inflorescences contain many flowers. The 2-12 cm long Blütenstandsschäfte are hairy fine white. The 1.2 to 3.5 cm long flower stems are hairy fine white.

The relatively large flowers are hermaphroditic, radial symmetry and fünfzählig double perianth. The five sepals are lance-shaped with a length of 4 to 6 mm. The five bright yellowish- green petals are 9-10 mm long. The whitish- green or cream Gynostegium has a short, tapered stem having a height of about 2 mm and a diameter of about 3 mm. The corona lobes are very broadly oval, broadly truncated at the top and about 4 mm long. The horn-shaped secondary extension is above all the way to tight. It is crescent-shaped and about as long as the staminal corona lobes. The stylus head is conical, cut off the top and about 3 mm long and 4 mm wide. The plants bloom from April to October.

The upright on upturned stems follicles are broad - fusiform and shortly acuminate with a length of 5-7 cm and a width of 2 to 3 cm above. Its surface is smooth. The seeds are very broad oval with a width of 13 mm and have a 1.5 mm long, light brown hair.

Occurrence

Asclepias erosa occurs in the U.S. states of Arizona, California, Nevada and Utah as well as in the Mexican state of Baja California. It grows at altitudes between about 50 to about 1500 meters. It grows in dry ravines, gullies and canyons where only irregular and seldom rains. Also along highways and railway lines it is found.

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