Tripleurospermum


Tripleurospermum is a genus in the chamomile tribe within the sunflower family. Mayweed is a common name for plants in this genus.
Most of the species are from Europe and temperate Asia although a few are from North America and North Africa. The species are placed in Matricaria by some authors.
Plants typically have lobed leaves that are composed of one to three opposite pairs cut almost to the leaf mid rib: they have indehiscent one-celled fruits that have 3-ribs and two resinous glands at the base, Matricaria species are distinguished from these species by lacking fruits with 3-ribs and the two glands.

Species

There are approximately 40 species recognised in the genus Tripleurospermum:Tripleurospermum ambiguum - Heilongjiang, Xinjiang, Kazakhstan, Mongolia, Uzbekistan, Iran, Kyrgyzstan, Altai KraiTripleurospermum anchialense Tripleurospermum auriculatum Rech.f. - Middle East including Egypt and Saudi ArabiaTripleurospermum baytopianum Tripleurospermum breviradiatum Tripleurospermum callosum E.Hossain - TurkeyTripleurospermum caucasicum Hayek - south-eastern Europe and south-western Asia from Switzerland to IranTripleurospermum conoclinium Hayek - Greece, TurkeyTripleurospermum corymbosum Tripleurospermum decipiens Bornm. - Turkey, Iran, CaucasusTripleurospermum disciforme Sch.Bip. - central and south-western AsiaTripleurospermum elongatum Bornm. - Turkey, GeorgiaTripleurospermum eskilense - TurkeyTripleurospermum fissurale - TurkeyTripleurospermum froedinii Tripleurospermum griersonii Tripleurospermum heterolepis - TurkeyTripleurospermum homogamum G.X.Fu - Xinjiang Tripleurospermum hookeri Tripleurospermum hygrophilum - TurkeyTripleurospermum inodorum - Europe, temperate and arctic Asia; naturalized in North America, New Zealand etc., considered a noxious weed in some placesTripleurospermum insularum Tripleurospermum kotschyi Tripleurospermum limosum Pobed. - China, Japan, Kazakhstan, Korea, Mongolia, Uzbekistan, Russia Tripleurospermum maritimum W.D.J.Koch - Arctic coasts of Eurasia and North AmericaTripleurospermum melanolepis Pobed. - Turkey, CaucasusTripleurospermum microcephalum Bornm. - Turkey, Iran, Syria, LebanonTripleurospermum monticola Bornm. - Azerbaijan, ArmeniaTripleurospermum parviflorum Pobed. - Greece, Ukraine, Crimea, European Russia, Caucasus, Turkey, Iran, Syria, Jordan, Lebanon, Iraq, Turkmenistan, Kazakhstan, UzbekistanTripleurospermum pichleri Bornm. - Bithynia region of TurkeyTripleurospermum repens - TurkeyTripleurospermum rosellum - Greece and Turkey including islandsTripleurospermum rupestre Tripleurospermum sannineum - LebanonTripleurospermum sevanense Pobed. - Turkey, Iran, Armenia

Formerly included

The genus is closely related to Heteromera, Matricaria, and Pyrethrum. Tripleurospermum breviradiatum - Matricaria breviradiata Tripleurospermum fuscatum - Heteromera fuscata Tripleurospermum philaenorum - Heteromera philaenorum