THYMELAEACEAE (Mezereum Family)

About 45 genera, 850 species, nearly worldwide.

Most species of Thymelaeaceae produce a variety of potentially toxic compounds including coumarins (and their glucosides and glycosides) and diterpenoid esters (phorbol esters), and are variously considered mildly to strongly poisonous. The family has limited economic importance, including some minor tropical timber trees and incense plants. The bark of species in several genera has been used in the production of paper and cordage in various parts of the world. The best-known genus is Daphne L., which comprises about 95 species native to Europe and Asia. Several Daphne species are cultivated as ornamental shrubs, a few (such as D. papyracea Wall. ex G. Don) are used in the production of thin, pliable papers, and others have been used medicinally as purgatives, emetics, and abortifacients. Additionally, bitter-tasting resins from some Daphne species have purported insecticidal properties and have been added to pills to encourage their swallowing without chewing.

Thymelaea passserina (L.) Coss. & Germ. (spurge flax) is a native of Europe that has become established sporadically in several states, including portions of Alabama, Illinois, Iowa, Kansas, Mississippi, Nebraska, Ohio, Texas, Washington, and Wisconsin (Holmes et al., 2000). Unlike most members of the family, it is a tap-rooted annual. Plants have ascending, slender stems to 60 cm tall, linear-lanceolate leaves to 15 mm long and small axillary clusters of flowers. The flowers are produced in the summer and are 2–3 mm long, perigynous with an urn-shaped, hairy hypanthium tipped with 4, minute, greenish yellow calyx lobes, but lacking a corolla. The 8 stamens are included in the hypanthium. Fruits are 1-seeded and indehiscent, with an ovoid body tapered into a short beak, and remain enclosed in the persistent hypanthium. Because of its sporadic occurrence to the east and west of Missouri, this nondescript, weedy species should be watched for in the state.