Difference between Swallow Wort and Swallowwort

SWALLOW WORT vs SWALLOWWORT: NOUN

The plant Euphorbia maculata.
Any of various plants of the genus Asclepias.
A tetterwort, Chelidonium majus or Sanguinaria canadensis.
A plant of the genus Stapelia.
A poisonous plant (Vincetoxicum officinale) of the Milkweed family, at one time used in medicine; -- also called white swallowwort.
See celandine.
The celandine, Chelidonium majus, once fancied to be used by swallows as a sight-restorer. Compare swallow-stone.
Hence, as a book-name, any plant of the genus Asclepias, the milkweed: applied also to the soma-plant, as formerly classed in Asclepias, and to an umbellifer, Elæoselinum (Thapsia) Asclepium, perhaps from its external resemblance to an asclepiad.
The European herb Cynanchum (Asclepias) Vincetoxicum, or white swallowwort, the plant anciently called asclepias. Also called vincetoxicum (which see) and tame-poison.
Any of several vines of the genus Cynanchum having clusters of small white or brownish-purple flowers and slender dehiscent pods.
Perennial herb with branched woody stock and bright yellow flowers
Tropical herb having orange-red flowers followed by pods suggesting a swallow with outspread wings; a weed throughout the tropics

Reed canary grass, Honeysuckles, Jewelweed, Swamp milkweed, Leafminer, Pondweed, Cow parsnip, Goutweed, Mullein, Marsh marigold, Pokeweed, Swallowwort, Greater celandine, Chelidonium majus, Celandine

Colicroot, Kidneywort, Sawwort, Spearwort, Thoroughwort, Bloodwort, Dropwort, Navelwort, Tetterwort, Swallow wort, Greater celandine, Chelidonium majus, Celandine, Blood flower, Asclepias curassavica

Toadflax, Bush honeysuckle, Tomato hornworm, Asclepias, Honeysuckles, Jewelweed, Swamp milkweed, Leafminer, Cow parsnip, Goutweed, Mullein, Marsh marigold, Pokeweed, Swallowwort, Celandine

Bullwort, Rosewort, Spurgewort, Sneezewort, Brownwort, Colicroot, Kidneywort, Sawwort, Spearwort, Thoroughwort, Bloodwort, Dropwort, Navelwort, Tetterwort, Celandine