30.
Helianthus pauciflorus
Nuttall, Gen. N. Amer. Pl. 2: 177. 1818.
Perennials
, 50—200 cm (rhizomatous).
Stems
erect, scabro-hispid.
Leaves
mostly basal; opposite, or opposite (proximal) and alternate; petioles 0—1 cm; blades lance-ovate to oblong-lanceolate, or rhombic-ovate to lance-linear, 5—27 × 2—6 cm, bases cuneate, margins serrate to subentire, abaxial faces sparsely hispid, sparsely, if at all, gland-dotted (cauline smaller).
Heads
1—10.
Peduncles
3—12 cm.
Involucres
hemispheric, 15—23 mm diam.
Phyllaries
25—35, ovate, 6—10 × 3—5 mm, (margins ciliate) apices acute, abaxial faces glabrate to hispid.
Paleae
9—10 mm, shallowly 3-toothed to subentire (apices ciliate, hairy).
Ray florets
10—20; laminae 20—35 mm (abaxial faces usually gland-dotted).
Disc florets
75+; corollas 6.5—7 mm, lobes usually reddish, sometimes yellow
;
anthers dark, appendages dark (style branches yellow).
Cypselae
5—6 mm, glabrate;
pappi
of 2 aristate scales 4.5—5 mm plus 1—4 smaller aristate scales 0.3—2 mm.
2
n
= 102 (subspecies unknown).
Subspecies 2 (2 in the flora): North America.
Variation within
Helianthus pauciflorus
is complex and is complicated by hybridization with
H. tuberosus
. Hybrids with
H. tuberosus
are known as
H.
×
laetiflorus
, which is frequently cultivated.
