''Lythrum hyssopifolia'' ( ''L. hyssopifolium'') is a species of flowering plant in the loosestrife family known by the common names hyssop loosestrife and grass-poly. It is native to Europe but it is known elsewhere, including parts of Australia and eastern and western North America, as an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

and sometimes a

weed A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

. It is rare in the United Kingdom, with occasional isolated populations. It often grows in moist habitats, such as

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...

es and wet agricultural fields,

rice paddies A paddy field is a flooded field of arable land used for growing semiaquatic crops, most notably rice and taro. It originates from the Neolithic rice-farming cultures of the Yangtze River basin in southern China, associated with pre-Aust ...

, for example. It is a mostly upright, branching annual or biennial herb growing 10 to 60 centimeters (4" to 24") tall. The oval leaves are arranged oppositely lower on the plant, and often alternately toward the top. They are up to 3 centimeters (1") in length. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is a terminal spike of flowers with pinkish petals up to half a centimeter (¼") long. The fruit is an oval capsule containing many minute seeds. The Latin word ''hyssopifolia'' (which occurs in several plant names) means "

hyssop ''Hyssopus officinalis'' or hyssop is a shrub in the Lamiaceae or mint family native to Southern Europe, the Middle East, and the region surrounding the Caspian Sea. Due to its purported properties as an antiseptic, cough reliever, and expecto ...

-leafed".

James Donn James Donn (1758–1813) was an English botanist and gardener. He was trained by William Aiton, a protege of Sir Joseph Banks and was Curator of the Cambridge University Botanic Garden, Cambridge, from 1790 until his death. His most important wo ...

, ''Hortus Cantabrigiensis: or, a Catalogue of Plants, Indigenous and Exotic (1809), p. 5

References

External links

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{{Taxonbar, from=Q159617 hyssopifolia Flora of Lebanon Plants described in 1753 Taxa named by Carl Linnaeus Flora of Malta