''Petunia exserta'' is a rare member of the genus '' Petunia'', endemic to the

Serras de Sudeste Serras de Sudeste (English: ''Southeastern Mountain Ranges'') is a dissected plateau, also named Planalto Dissecado de Sudeste (''Southeastern Dissected Plateau'') or Escudo Sul-Rio-Grandense (''Shield of Rio Grande do Sul''), located in the sou ...

in southern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

. First described in 1987, only fourteen plants were found in the wild during an expedition in 2007. In the wild, the plant is found growing only in shaded cracks on sandstone towers. It is the only ''Petunia'' species that is naturally pollinated by hummingbirds, and the only red flowered ''Petunia'' species.

Description

''Petunia exserta'' has a bright red corolla with distinctive exserted

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s and stigma, the latter which are typically associated with hummingbird pollination. It shares the erect habit, and similar corolla, pollen, and stalk attributes of ''

Petunia axillaris ''Petunia axillaris'', the large white petunia, wild white petunia or white moon petunia, is an annual herbaceous plant in the family Solanaceae, genus ''Petunia''. It is native to temperate South America. The plant's flowers, the only white on ...

'' and '' Petunia secreta''. The flowers have no fragrance, which is not necessary for attracting hummingbirds, who have little sense of smell. The red color is due to several

anthocyanin Anthocyanins (), also called anthocyans, are water-soluble vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart gave the name Anthokyan to a chemical compo ...

pigments, which are different from the cause of red color in modern hybrid petunias.

Threats

In addition to its very limited range, ''P. exserta'' is also threatened because it so easily hybridizes with other ''Petunia'' species in its native range, especially with ''

'', thus producing offspring that are hybrids rather than the species. The plant is increasingly being sold in horticulture, so the threat to its survival is only in its native habitat.

References

External links

Kew Plant List
{{Taxonbar, from=Q7179423 exserta Flora of Brazil