Fig 141. [Black Swallow-wort. Cynanchum nigrum] (L.) Pers. Vincetoxicum nigrum Moench.
![[Black Swallow-wort. Cynanchum nigrum]](#1525880611323293367_fig-141.jpg.id-4497281048039064698.wrap-0.html.html){kind=link}
Black Swallow-wort. Cynanchum nigrum (L.) Pers. Vincetoxicum nigrum Moench. Smooth pods of the vine about 5 cm. long; seeds brown when dry, much flattened, concave, obovate, 6–8 mm. long, nearly surrounded by a wing margin or hem, the small end truncate. The concave side bears a slender vertical ridge (raphe) for over half its length, both sides bearing fine short ridges. Before escaping from the pods, the small end of the seed contains a cluster of spreading silky hairs. Introduced from Europe; not yet common, but it is persistent where once started.
MORNING GLORY FAMILY. CONVOLVULACEAE.
Fig 142. [Small Bindweed. Convolvulus arvensis] L.
![[Small Bindweed. Convolvulus arvensis]](#1525880611323293367_fig-142.jpg.id-4529627315261699353.wrap-0.html.html){kind=link}
Small Bindweed. Convolvulus arvensis L. Color of seeds dull dark brown, coarsely roughened, oval, 3–4 mm. long, one face convex, the other face sloping to the edges from a broad, central ridge, becoming mucilaginous when soaked in water. Introduced from Europe. Seldom, if ever, seeding in Michigan. On dry, poor land.
