Helianthella

Helianthella uniflora

The dwarf sunflowers ( Helianthella ) are a genus of flowering plants in the subfamily of herbaceous within the sunflower family ( Asteraceae). The botanical genus name is derived from the genus name of the sunflower Helianthus and the Latin - ella as a reduction ( diminutive ). In genus Helianthella there are about nine to ten species.

Description

Helianthella species grow as perennial herbaceous plants usually reach heights of growth of about 20 to 150 cm depending on the type. The upright stems are often branched. The to -earth and alternate, basal and distributed to the stems arranged leaves are usually stalked. The leaf blade is easy with three or five leaf veins starting at or near the Spreitenbasis. The leaf margin is smooth. The leaf surfaces are smooth or hairy.

The little head shaped inflorescences are borne in branched, schirmtraubigen total inflorescences terminal or individually to two to 15. The circular flower baskets have diameters of from 1 to 5 centimeters. In more or less three rows are 22 to 32 bracts; they are different in shape and size almost equal to strong. The inflorescence soils are more or less convex. There are chaff leaves present. The flower heads contain eight to 21 ray florets and disc florets 30 to over 200. The ungeschlechtigen ray florets ( = ray florets ) are yellow and the tongue ends tridentate. The hermaphrodite, fertile florets ( = disc florets ) are usually yellow or brown to purple with five corolla lobes.

The wrinkled achenes are brown. The pappus consists of two pfriemförmigen dandruff and sometimes in addition to more than four smaller, slashed scales, which can sometimes be all grown more or less; the pappus may be absent.

Systematics and distribution

The distribution of the genus Helianthella ranges from northern Mexico with four species to western North America with six species.

The first publication of the genus Helianthella in 1842 by John Torrey and Asa Gray in Synoptical Flora of North America, 2, 333 The genus belongs to the subtribe Helianthella Enceliinae from the tribe Heliantheae in the subfamily of herbaceous within the sunflower family ( Asteraceae).

In the genus Helianthella there are about nine to ten species. Here is a list of all the species:

  • Helianthella californica A. Gray: With three subspecies in the western United States: Helianthella californica A. Gray subsp. californica
  • Helianthella californica subsp. nevadensis (Greene) W.A.Weber
  • Helianthella californica subsp. shastensis ( W.A.Weber ) W.A.Weber
  • Helianthella gypsophila var calcarea B.L.Turner
  • Helianthella gypsophila BLTurner var gypsophila

No longer belong to the genus:

  • Helianthella argophylla ( DCEaton ) A.Gray ⇒ Tithonia argophylla DCEaton
  • Helianthella covillei A.Nelson ⇒ Enceliopsis covillei ( A.Nelson ) SFBlake
  • Helianthella grandiflora Torr. & A. Gray ⇒ Phoebanthus grandiflora ( Torr. & A. Gray ) SFBlake
  • Helianthella tenuifolius Torr. & A. Gray ⇒ Phoebanthus tenuifolius ( Torr. & A. Gray ) SFBlake

Swell

  • William A. Weber: Helianthella in the Flora of North America, Volume 21, page 114: - Online.
  • William A. Weber: New names and Combinations in Asteraceae: Heliantheae - Ecliptinae in Phytologia, 85, (1 ), 1998, S 19-21. .
Asteroideae Perennial plant Pappus (flower structure) Durango Arizona Basin and Range Province Black Hills Montana Nevada Oregon South Dakota Chihuahua (state)
384043
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