Helianthella tenuifolia

Interesting Facts

Description

Family Compositae

The largest family of flowering plants , the Compositae (Asteraceae), comprising about 1,100 genera and more than 20,000 species and characterized by many small flowers arranged in a head looking like a single flower and subtended by an involucre of bracts. A head may consist of both ray flowers and disk flowers, as in the sunflower, of disk flowers only, as in the burdock, or of ray flowers only, as in the dandelion.

Genus Helianthella

Perennials , 20-150 cm. Stems erect , usually branched. Leaves basal and cauline; opposite (proximal ) and alternate; usually petiolate (at least proximal) ; blades (usually 3- or 5-nerved from at or near bases ) elliptic , lanceolate, lance-linear , linear , oblanceolate , ovate , ovate-lanceolate, or spatulate , bases mostly cuneate, margins entire, faces glabrous or hairy . Heads radiate , borne singly or (2-15+) in corymbiform arrays. Involucres campanulate to hemispheric or broader, 10-50 mm diam. Phyllaries persistent , 22-32+ in ± 3 series (mostly deltate-ovate or ovate to lanceolate, linear, or oblong , subequal or unequal, outer sometimes foliaceous ). Receptacles ± convex , paleate (paleae falling with cypselae, conduplicate , scarious or chartaceous ). Ray florets 8-21, neuter ; corollas ± yellow. Disc florets 30-200+, bisexual , fertile ; corollas yellow or purple to brown, tubes shorter than or equaling throats , lobes 5, deltate (abaxially hairy). Cypselae (brownish) ± compressed , obovate to obcordate (margins usually ± winged , usually ± ciliate , faces glabrous or strigose ) ; pappi 0, or persistent, of 2 ± subulate scales plus 0-4+ shorter, lacerate scales (sometimes all ± connate ). x = 15.

Species 9: w North America, n Mexico.[1]

Taxonomy

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Domain: Eukaryota () - Whittaker & Margulis,1978 - eukaryotes
- Kingdom: Plantae () - Haeckel, 1866 - Plants
  - Subkingdom: Viridaeplantae () - Cavalier-Smith, 1981
    - Phylum: Tracheophyta () - Sinnott, 1935 ex Cavalier-Smith, 1998 - Vascular Plants
      - Subphylum: Euphyllophytina ()
        Class: Spermatopsida () - Brongniart, 1843
        Subclass: Asteridae () - Takhtajan, 1967
        Superorder: Campanulanae () - Takhtajan Ex Reveal, 1992
        Order: Asterales () - Lindley, 1833
        Family: Compositae () - Giseke, 1792, nom. cons., nom. alt.
        Genus: Helianthella () - J. Torrey & A. Gray, 1842 - Little sunflower [Generic name Helianthus and Latin -ella, diminutive]
        Specific epithet: tenuifolia
        Botanical name: - Helianthella tenuifolia