Table 22. Asclepias tuberosa.

Fig. 1. A branch of Asclepias tuberosa, of the natural size.
2. A flower.
3. The Nectary.
4. The calix and germ.

This image is from W. Barton's Vegetable Materia Medica, 1817 (Vol. I), 1818 (Vol. II), Asclepias.