Asclepias tuberosa L. 
Family: Asclepiadaceae
butterfly milkweed,  more
Asclepias tuberosa image
Max Licher  
 
Plant: perennial herb; stems erect or ascending, branching only in the inflorescence, 20-80 cm tall Leaves: irregularly alternate, usually crowded, distinctly short-petiolate, the petioles 1-2 mm long, the blades lanceolate, linear-lanceolate or narrowly oblong, 2-10 cm long, 3-15(-22) mm broad, acute apically, acute to mostly obtuse, rounded, truncate, or subhastate at the base, pilose beneath particularly on the veins, pilose to somewhat hirsute above; no milky sap Inflorescence: UMBELS lateral and subterminal, simple to irregularly compound, 3-5 cm broad, typically clustered at the uppermost nodes forming a more or less flat-topped to rounded secondary inflorescence, the peduncles indistinct to mostly 1-6 cm long Flowers: medium size; calyx lobes 2-3 mm long; corolla bright orange or less commonly yellow, the lobes 6-8 mm long; hoods orange to yellow, erect or ascending, lanceolate to oblong, attenuate above the middle to a rounded apex, 4-5.5 mm long, 1-2 mm broad, ca. 1.5-3 mm longer than the gynostegium, the horns attached below the middle of the hoods, digitate, exserted 1-2 mm and more or less arching over the stigma head; anther wings 1.8-2 mm long; corpusculum 0.2-0.3 mm long, the pollinia 1.2-1.4 mm long Fruit: FOLLICLES erect on deflexed pedicels, 7-13 cm long REFERENCES: Sundell, Eric. 1994. Asclepiadaceae. J. Ariz. – Nev. Acad. Sci. Volume 27, 169-187.
Asclepias tuberosa image
Max Licher  
Asclepias tuberosa image
Max Licher  
Asclepias tuberosa image
Max Licher  
Asclepias tuberosa image
Max Licher  
Asclepias tuberosa dot map
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