Crooked Run Valley
smooth oxeye (Heliopsis helianthoides)
Buphthalmum helianthoides Linnaeus
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name for smooth oxeye is Heliopsis helianthoides (L.) Sweet.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL DESCRIPTION:
Habit: Smooth oxeye is a perennial plant, 3-5' tall, branching occasionally becoming bushy in open situations. The stems are light green to reddish green, variably pubescent or hairy, and terete to slightly angular.
Leaves: Pairs of opposite leaves are distributed evenly along these stems. These leaves are 2½–5" long and 1–3½" across; they are cordate-ovate, ovate, or lanceolate in shape, while their margins are coarsely serrated. The upper leaf surface is medium to dark green and usually rough-textured from minute stiff hairs, while the lower leaf surface is light green and glabrous to short-pubescent. Primary veins of the leaves are pinnately arranged. On each leaf, 2 prominent lateral veins become separated from the central vein near its base. Secondary veins of the leaves form reticulated networks that are visible on the leaf undersides. The petioles are up to ¾" long, partially winged, and more or less pubescent.
Flowers: The upper stems terminate in flowerheads spanning about 1½–3" across; these flowerheads are usually more or less erect. Each flowerhead consists of 8-20 ray florets that surround numerous disk florets. The petaloid rays of each flowerhead are yellow to deep golden yellow, oblong or oblong-elliptic in shape, and slightly notched at their tips. The tiny corollas of both the ray florets and disk florets are short-tubular in shape, deep golden yellow to orange-yellow, and 5-lobed; the corolla lobes of these florets are triangular in shape and spreading to recurved. Both the ray florets and disk florets of the flowerheads are fertile. At the base of each flowerhead, there are several outer phyllaries (floral bracts) that are arranged in a single series. These phyllaries are light to medium green, more or less pubescent, and oblong-ovate in shape, tapering abruptly to blunt tips that are somewhat recurved. There are also several inner phyllaries that are arranged in a single series. These phyllaries are similar to the outer phyllaries, but their tips are appressed along the base of the flowerhead, rather than recurved. The peduncles of the flowerheads are 1-6" long, light green, terete to slightly angular, and more or less pubescent.
Fruit/seeds: After blooming the florets are replaced by achenes that are 4-5 mm. long, oblongoid-oblanceoloid in shape, somewhat flattened, and dark-colored. These achenes lack tufts of hair, nor do they have significant scales at their apices.
Roots: The root system is fibrous.
REGENERATION PROCESS: Smooth oxeye propogates itself by reseeding.
HABITAT TYPES: Habitats include black soil prairies, river-bottom prairies, grassy meadows in wooded areas, open woodlands, woodland borders, savannas, thickets, limestone glades, banks of streams, and areas along railroads where prairie remnants occur.
SITE CHARACTERISTICS: Smooth oxeye prefers full to partial sun, moist to mesic conditions, and loamy soil, although rocky ground and clay-loam are tolerated. This plant is easy to cultivate and it has a long blooming period during the summer.
SEASONAL DEVELOPMENT: The blooming period occurs from early summer to late summer, lasting about 2-3 months for a colony of plants.
GENERAL DISTRIBUTION: Smooth oxeye naturally occurs throughout the eastern United States and Canada, from Florida to the Canadian Maritime provinces (excepting Nova Scotia) and extends west into the Great Plains states and provinces and into the eastern portions of the desert Southwest. It does not naturally occur in the far Southwest or western portions of the Rocky Mountains. It also does not naturally occur in the far Pacific states of California or Oregon, but does occur in Washington state (probably introduced).
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: The nectar and pollen of the flowerheads attract a wide variety of insects, including honeybees, bumblebees, little carpenter bees (Ceratina spp.), digger bees (Melissodes spp.), cuckoo bees (Coelioxys spp., Triepeolus spp.), leaf-cutting bees (Megachile spp.), Halictid bees (Agapostemon spp., Lasioglossum spp.), Andrenid bees (Andrena spp., Heterosarus spp.), thread-waisted wasps (Ammophila spp.) and other wasps, Syrphid flies (Eristalis spp., Toxomerus spp.), bee flies (Exoprosopa spp.), the goldenrod soldier beetle (Chauliognathus pennsylanicus) and other beetles, painted lady butterflies (Vanessa spp.) and other butterflies, and skippers. These floral visitors cross-pollinate the flowerheads. Other insects feed on the leaves, stems, seeds, and other parts of false sunflower. These species include a leaf beetle (Physonota helianthi), leaf-mining larvae of a Tischeriid moth (Astrotischeria heliopsisella), stem-boring larvae of the rigid sunflower borer moth (Papaipema rigida), floret- and seed-eating larvae of a fly (Melanagromyza virens), and a seed bug (Lygaeus turcicus). Little is known about this plant's relationships to vertebrate animals, but they are probably similar to those of sunflowers (Helianthus spp.). Hoofed mammalian herbivores probably browse on the young foliage, while upland gamebirds, granivorous songbirds, and small rodents probably eat the seeds.