''Hartwrightia'' is a genus of North American flowering plants in the tribe Eupatorieae of the family Asteraceae.D.J.N.Hind & H.E.Robinson. 2007. Tribe Eupatorieae In: ''The Families and Genera of Vascular Plants'' vol.VIII. (Joachim W.Kadereit & Charles Jeffrey, volume editors. Klaus Kubitzky, general editor). Springer-Verlag. Berlin, Heidelberg. The genus contains a single species, ''Hartwrightia floridana'', native to the US states of Georgia and Florida. The species is sometimes referred to by the common name Florida hartwrightia.
Although superficially similar to some species in '' Eupatorium'', it can be distinguished by having a basal rosette of leaves, flowers of a different shape, and the fruit which lacks the parachute-like pappus found in '' Eupatorium''. The plant is about one meter tall. It flowers in the fall and the flowers are white to pink or blue.
The genus is named for plant collector Samuel Hart Wright, 1825–1905.
Taxonomy
''Hartwrightia'' is classified in the subtribe Liatrinae of the tribe Eupatorieae, along with, for example, '' Liatris'', ''
Carphephorus
''Carphephorus'' is a genus of North American plants in the family Asteraceae. They are native to the southeastern United States from Louisiana to Virginia. Plants of this genus are known commonly as chaffheads.Garberia''. Molecular data, while placing ''Hartwrightia'' firmly within subtribe Liatrinae, give mixed results regarding its closest relative. The nuclear ITS/ETS regions place it firmly with ''Trilisa'', with which it shares multiple
synapomorphies
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...
but also differs at multiple sites. In contrast, it is almost an exact match in the
plastid
The plastid (Greek: πλαστός; plastós: formed, molded – plural plastids) is a membrane-bound organelle found in the Cell (biology), cells of plants, algae, and some other eukaryotic organisms. They are considered to be intracellular endosy ...
DNA sequences with ''Carphephorus corymbosus''. These results suggest that ''Hartwrightia'' may be of hybrid origin but is transgressive from either putative parental lineage for multiple morphological characters
Ecology
''Hartwrightia floridana'' is a
herbaceous perennial
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widel ...
which grows in the southeastern United States ( Georgia and Florida). It is found in open areas, for example in pine flatlands, but is not tolerant of grazing or solid forest cover. It seems to do better in the presence of regular fires. It is considered threatened and the biggest threat is loss of habitat. It requires wet soil, and is sensitive to hydrological changes. The seed is a sticky
achene
An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...
without the large pappus which would suggest wind dispersal, so it is presumed to be transmitted by animals.