Monographs Details: Asclepias speciosa Torr.
Authority: Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Description:Species Description - Colonial by roots; stem stout, erect, to 1 m, hairy; lvs ovate to lance-ovate or ovate-oblong, 10–15 cm, broadly rounded or subcordate at base, hairy beneath; petioles
3–6 mm; umbels usually few, 5–7 cm wide; peduncles stout, 3–7 cm; cor greenish-purple, its lobes 10–15 mm; hoods 10–15 mm, abruptly narrowed below the middle to a linear-oblong tip; horns short, inflexed; fr densely tomentose and beset with soft filiform processes; 2n=22. Moist prairies; Man. to Minn., Io., and Okla., w. to B.C. and Calif. July, Aug.
Common Names:showy milkweed