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Published In: Hortus Britannicus 2: 487. 1826. (Hort. Brit.) Name publication detailView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 8/11/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native

 

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1. Heliopsis helianthoides (L.) Sweet (oxeye, false sunflower, sunflower heliopsis)

Pl. 283 g–i; Map 1204

Plants perennial herbs, with fibrous roots and sometimes a short, stout rhizome. Stems 40–150 cm long, erect or ascending, usually several-branched, with fine longitudinal lines or ridges, glabrous to sparsely to moderately pubescent with slender, ascending hairs (these rarely rough to the touch) or more commonly moderately roughened with short, stout, ascending, broad-based hairs (and sometimes also scattered, longer hairs). Leaves opposite or the uppermost few alternate, sessile or relatively short-petiolate, the lowermost leaves sometimes with longer petioles, the bases minutely expanded and wrapping around the stem (leaving a low ridge around the stem after the leaves are shed), the petiole sometimes with sparse to moderate, long, spreading hairs. Leaf blades 3–15 cm long, oblong-lanceolate to ovate or ovate-triangular, short-tapered or angled to more or less truncate at the base, tapered to a sharply pointed tip, the margins sharply and finely to coarsely toothed and minutely hairy, the upper surface glabrous to minutely pubescent with slender, sometimes broad-based hairs or more commonly strongly roughened with short, stout, broad-based hairs, the undersurface glabrous or minutely pubescent with slender hairs (occasionally with a few longer hairs along the midvein) or more commonly strongly roughened with short, stout, broad-based hairs, both surfaces also with scattered, sessile, spherical, yellow glands. Inflorescences of solitary or less commonly 2–4 heads at the branch tips and from the upper leaf axils, the heads usually with long, bractless, glabrous or roughened stalks. Heads radiate. Involucre 6–16 mm long, 10–22 mm in diameter, cup-shaped to broadly bell-shaped, the bracts in 2 or 3 subequal series. Involucral bracts 17–29, lanceolate to ovate, rounded to sharply pointed at the tip, the outer surface usually minutely hairy or roughened, those of the outer series often somewhat longer than the others and with loosely ascending to spreading tips, green, those of the inner series slightly shorter, usually somewhat yellowish green and somewhat scalelike, more strongly ascending at the tip. Receptacle conical, elongating somewhat as the fruits mature, with chaffy bracts subtending the ray and disc florets, these 8.0–8.5 mm long, oblong-lanceolate, concave and wrapped around the florets. Ray florets 8–16(–35), pistillate (with a 2-branched style exserted from the short tube at flowering), the corolla 15–40 mm long, relatively broad, pale yellow to orangish yellow, glabrous or nearly so, persistent and turning papery at fruiting. Disc florets 10–80, perfect, the corolla 4–5 mm long, greenish yellow to brownish yellow, glabrous, not expanded at the base or persistent at fruiting. Style branches with the sterile tip somewhat elongate and tapered. Pappus of the ray and disc florets absent or the disc florets with 2–4 minute teeth. Fruits 3.0–3.5 mm long, narrowly rectangular to slightly wedge-shaped in outline, strongly 3-angled (ray florets) or 4-angled (disc florets), the surface usually appearing finely pebbled, glabrous, dark brown to black, somewhat shiny. 2n=28. May–September.

Scattered nearly throughout the state but apparently absent from most of the Mississippi Lowlands Division (eastern U.S. west to North Dakota and New Mexico; Canada). Mesic to dry upland forests, savannas, glades, upland prairies, sand prairies, banks of streams and rivers, seeps, and ledges and tops of bluffs; also margins of crop fields, pastures, fencerows, railroads, and roadsides.

Oxeye is sometimes cultivated as an ornamental in gardens. Examination of specimens in herbaria suggests that many students and botanists have difficulty in distinguishing this species from some members of Helianthus. This may be because of difficulties in interpretation of the character of persistent papery ray corollas. More reliably, the flowering heads of Heliopsis contain ray florets with a well-developed ovary and an exserted, branched style, whereas those of Helianthus contain ray florets with a slender, nonfunctional, stalklike ovary and the style apparently absent (very short, included in the short, tubular portion of the ray corolla, and undivided at the tip). The ray florets of Heliopsis develop well-formed, conspicuously 3-angled achenes, whereas in Helianthus the ovary portion of the ray florets is frequently shed with the corolla or, when persistent, is very difficult to observe.

Fisher (1957, 1958) treated H. helianthoides as comprising three morphologically overlapping subspecies with different centers of distribution. In particular, his ssp. occidentalis and ssp. scabra were noted to intergrade for most of the characters separating them. In fact, Fisher’s mapped ideograms representing character coding for features such as petiole length and head stalk length seem to show a clinal north-to-south variation in the central portion of the United States with Missouri indicated to occupy part of the main geographic zone of intermediacy. Other authors, such as Steyermark (1963) and Turner (1988a), also commented on the large number of specimens intermediate for one or several of the purported differences between ssp. occidentalis and ssp. scabra. More recent collections continue to reinforce the problems in separating Missouri material of these two variants. Accordingly, they have been reduced to a single taxon in the present treatment. Steyermark (1963) and Turner (1988a) also chose to treat infraspecific variation within H. helianthoides at the varietal rather than subspecific level, which seems reasonable in light of the overlapping ranges of the taxa and the lack of cytological differences between them.

 

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1 1. Leaves glabrous or minutely pubescent with slender hairs (occasionally with a few longer hairs on the undersurface midvein), those of the upper surface sometimes broad-based and rough to the touch; stems glabrous or sparsely to moderately pubescent with slender, ascending hairs, these rarely rough to the touch ... 1A. VAR. HELIANTHOIDES

Heliopsis helianthoides (L.) Sweet subsp. helianthoides
2 1. Leaves strongly roughened with short, stout, broad-based hairs on both surfaces; stems also moderately roughened with short (and sometimes also longer), stout, broad-based hairs ... 1B. VAR. SCABRA Heliopsis helianthoides subsp. scabra
 


 

 
 
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