''Ruellia strepens'', commonly known as limestone wild petunia, limestone ruellia, smooth wild petunia, or wild petunia is a species of flowering plant in the family

Acanthaceae Acanthaceae is a family (the acanthus family) of dicotyledonous flowering plants containing almost 250 genera and about 2500 species. Most are tropical herbs, shrubs, or twining vines; some are epiphytes. Only a few species are distributed in tem ...

, native to warmer parts of the central and eastern United States. A

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 wid ...

herb, it prefers to grow in moist to mesic, partly shady areas such as streamsides and bottomland forests. In the garden it is hardy to

USDA zone A hardiness zone is a geographic area defined as having a certain average annual minimum temperature, a factor relevant to the survival of many plants. In some systems other statistics are included in the calculations. The original and most wide ...

5, and can tolerate nearly full shade.

Description

''R. strepena'' grows up to tall, branching occasionally. The green stems either smooth or sparsely hairy. The leaves are opposite on the stem, have short petioles, and are

lanceolate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular ...

ovate Ovate may refer to: * Ovate (egg-shaped) leaves, tepals, or other botanical parts *Ovate, a type of prehistoric stone hand axe *Ovates, one of three ranks of membership in the Welsh Gorsedd *Vates In modern English, the nouns vates () and ova ...

, tapering to a sharp point at the end. They measure up to long and across. Their margins are smooth or slightly undulate. The flowers are lavender to bluish, growing from nodes near the middle of the stems. They have 5 flaring lobes and are tubular, measuring up to long. Although many herbaceous plants cease growing or even die back after blooming, ''R.strepens'' continues to get bigger as its fruits mature, resulting in late season plants that might be twice as tall as they were when flowering.

Etymology

The genus name ''Ruellia'' honors

Jean Ruelle Jean Ruel (1474 – 24 September 1537), also known as Jean Ruelle or Ioannes Ruellius in its Latinised form, was a French physician and botanist noted for the 1536 publication in Paris of ''De Natura Stirpium'', a Renaissance treatise on botany. ...

, a French physician and botanist (1474 – 1537). Its specific epithet ''strepens'' refers to the rustling noises the plant's seeds make as they uncoil and bury themselves into the ground.

Distribution and habitat

''R. strepena'' is native in the United States from Nebraska to the west, Texas and Florida to the south, Michigan and Pennsylvania to the north, and the east coast to the east. It is listed as endangered in Michigan and North Carolina and critically imperiled in South Carolina. It lives in bottomland forests, rich upland forests, river and stream banks, and edges of ponds and lakes. It can also be found occasionally in bottomland prairies and fens, pastures, moist roadsides, and railroads.

References

{{Taxonbar, from=Q1532177 strepens Endemic flora of the United States Flora of Nebraska Flora of Kansas Flora of Oklahoma Flora of Texas Flora of Iowa Flora of Missouri Flora of Illinois Flora of Indiana Flora of Michigan Flora of Ohio Flora of West Virginia Flora of Pennsylvania Flora of New Jersey Flora of the Southeastern United States Plants described in 1753 Taxa named by Carl Linnaeus