Prenanthella

{{Short description|Genus of flowering plants}}

{{Speciesbox

|image =

|display_parents = 4

|genus = Prenanthella

|parent_authority = Rydb.

|species = exigua

|authority = (A.Gray) Rydb.

|synonyms = Lygodesmia exigua

}}

Prenanthella is a monotypic genus of flowering plants in the family Asteraceae.Ford, V. S., et al. (2006). [https://web.archive.org/web/20060615051730/http://www.amjbot.org/cgi/content/full/93/3/480 Species divergence and relationships in Stephanomeria (Compositae): PgiC phylogeny compared to prior biosystematic studies.] American Journal of Botany 93: 480-90. It contains the single species Prenanthella exigua, which is known by the common name brightwhite.[http://plants.usda.gov/java/profile?symbol=PREX USDA Plants Profile] It is native to the southwestern United States from California to Texas and it is known as far north as Idaho. Its habitat includes desert and woodlands. This annual herb produces a slender, branching stem reaching a maximum height near 40 centimeters. It has a sparse coating of glandular hairs and contains a milky juice. Most of the leaves are located near the base of the stem. They are widely lance-shaped and sometimes divided into segments. Smaller leaves occur higher on the stem; these may be reduced to scale-like structures, leaving the stem mostly bare. The inflorescence is a wide open panicle of several flower heads. Each small head is cylindrical and narrow, its base wrapped in lance-shaped phyllaries. At the tip of the head bloom 3 or 4 flowers, which are ray florets; there are no disc florets. Each floret has is white to pale pink and has a toothed tip. The fruit is a white achene with a pappus of white bristles.