Helianthus laciniatus
Helianthus atrorubens
alkali sunflower
purpledisc sunflower, purpledisk sunflower
erect, usually strigose or hispid to glabrate.
erect, proximally villous to strigoso-hispid, distally hispid or glabrate.
cauline; opposite or alternate;
sessile;
blades (green or grayish, 1- or 3-nerved) lanceolate, 5–9 × 0.5–3.5 cm, bases ± cuneate, margins entire or irregularly toothed to lobed, faces strigose to strumose, gland-dotted (adaxial sometimes glaucous).
mostly basal; opposite;
petioles 4–25 cm (usually winged at least 1/2 their lengths);
blades lanceolate to ovate, 7–26 × 3–10 cm, bases broadly cuneate to nearly truncate (often decurrent onto petioles), margins serrate to crenate, abaxial faces strigoso-hispid (hairs of midribs1+ mm), not gland-dotted (cauline to 8 pairs proximal to heads, ovate to elliptic, smaller).
4–13 cm.
0.3–17 cm.
hemispheric, 10–24 mm diam.
broadly hemispheric, 9–16 mm diam.
14–20;
laminae ca. 8–11 mm.
10–15;
laminae 15–22 mm (abaxial faces not gland-dotted).
40+;
corollas 4.8–5.8 mm, lobes reddish;
anthers purplish, appendages reddish (style branches yellow).
75+;
corollas 4–6 mm, lobes reddish;
anthers dark, appendages dark (style branches yellow).
16–21, lanceolate, 6–7.5 × 1.8–2.5 mm (often subequal), (margins ciliate) apices acute, abaxial faces hispidulous or strigose to glabrate, gland-dotted.
15–22, broadly ovate to oblong, 7–9 × 4–5 mm, (margins ciliolate) apices obtuse to acute, sometimes mucronate, abaxial faces usually glabrous.
1–9.
(1–)3–15+.
2.7–3.5 mm, glabrate;
pappi of 2(–3) aristate scales 1.4–2.5 mm.
2.8–3 mm, glabrous or distally puberulent;
pappi of 2 aristate scales 2.5–2.8 mm.
7–7.8 mm, entire or 3-toothed (apices obtuse to acute, hispid-ciliate to glabrate).
4–5.5 mm, ± 3-toothed to entire.
= 34.
= 34.
Helianthus laciniatus
Helianthus atrorubens
Helianthus laciniatus reaches the northern extent of its range in New Mexico and Texas; it is relatively common in the Chihuahuan Desert areas of Mexico. It is similar to H. ciliaris; it usually has hairy stems as well as denser leaf indument that includes a greater number of subsessile, glandular hairs.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Helianthus atrorubens and H. silphioides form a morphologically similar pair of species that share the distinctive feature of relatively broad, tightly appressed phyllaries with apices obtuse to acute. Helianthus atrorubens has a more easterly geographic distribution along the Piedmont and the Atlantic coastal plain and the southern Appalachian Mountains; distribution of H. silphioides is centered in the Ozark region. In general, H. silphioides differs in its usually well developed cauline leaves, and basal leaves with winged petioles that are less than half the total lengths. Involucres with phyllaries tightly appressed are also observed in H. occidentalis and H. pauciflorus subsp. pauciflorus, which differs in having the phyllary apices acute to acuminate as well as in usually having abaxial faces of leaves and ray laminae densely gland-dotted.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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