Cynanchum louiseae (Black swallowort)

Cynanchum louiseae Kartesz & Gandhi

Black swallowort, Louise’s swallow-wort

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Asteridae	A large class that encompasses asters
Order	Gentianales	Gentians, coffee, gardenias, frangipani, many others
Family	Asclepiadaceae	Includes some herbs, twining shrubs, lianas, leafless stem succulents, rarely trees
Genus	Cynanchum	From the Greek kyon or kynos, “dog,” and anchein, “to strangle,” in reference to its supposed use or capacity as a dog poison, or because the vines can strangle an animal
Species	louiseae

About plant names...

Black swallow-wort is native to Italy, France, Portugal, and Spain. It is an invasive in North America, where it initially escaped from a botanical garden in 1854.

Identification: These vines have oval-shaped leaves with pointed tips, 3-4" (7.6-10 cm) × 1-2" (2.5-5 cm) wide, growing in opposing pairs along the vine. They reach heights of 6' (1.8 m). Small ⅛-¼" (3.2-6.3 mm) star-shaped flowers are dark purple to nearly black, with white hairs, and occur in clusters of 1-5. Fruits are slender and tapered, 1-3" (2.5-7.6 cm) long and ¼" (6.3 mm) wide, resembling those tiny hyperatomic peppers that spice up many Asian dishes. Older fruits turn from green to brown.

Photo by urtica on Flickr (Jenn Forman Orth). Flowers are about ¼" (6.3 mm) across.

Online References:

Cynanchum louiseae on Discover Life

Cynanchum louiseae on the Plant Conservation Alliance’s Alien Plant Working Group Least Wanted List

Cynanchum louiseae on the Connecticut Botanical Society's Connecticut wildflowers site

Cynanchum louiseae on Kansas Wildflowers and Grasses

Cynanchum louiseae on Invasive.org, Center for Invasive Species and Ecosystem Health

Cynanchum louiseae on Forestry Images

Cynanchum louiseae on the USDA Forest Service's Fire Effects Information Database

10/2/2010 · Wiccopee, NY
≈ 4½ × 7" (11 × 17 cm)

9/19/2013 · Harvard, Massachusetts
≈ 6 × 6" (16 × 16 cm)

Cynanchum nigrum (L.) Pers. non Cav.

Vincetoxicum nigrum (L.) Moench

Cynanchum louiseae description by Thomas H. Kent, last updated 25 May 2020.

10/2/2010 · Wiccopee, NY
≈ 4 × 6" (10 × 15 cm)

9/19/2013 · Harvard, Massachusetts
≈ 12 × 8" (31 × 21 cm)

10/2/2010 · Wiccopee, NY
≈ 7 × 11" (18 × 27 cm)

9/19/2013 · Harvard, Massachusetts
≈ 8 × 6" (20 × 14 cm)

10/2/2010 · Wiccopee, NY
≈ 11 × 7" (27 × 18 cm)

Range:

About this map...