Basis for Listing

Symphoricarpos orbiculatus is native to prairie and prairie-like habitats in the central and eastern United States, which may or may not include Minnesota. Although several regional plant manuals report this species from Minnesota (Fernald 1950; Great Plains Flora Association 1986), none provide supporting documentation. Other sources are more equivocal; for example, Ownbey and Morley (1991) say "possibly present in the state only by introduction from farther east or south". Smith (2008) is even more doubtful, stating "... there is no strong evidence that it is either native or naturalized in Minnesota". As of 2010, there are no known voucher specimens of S. orbiculatus in any Minnesota herbarium that were definitively collected from a native Minnesota population (the Houston County specimen is believed to be from an introduced population). Symphoricarpos orbiculatus was listed as a special concern species in Minnesota in 1984 but given the question of nativeness, it is currently being considered for delisting.

  Description

Symphoricarpos orbiculatus is an erect shrub 0.5-2 m (1.6-6.6 ft.) tall. The branches are erect or ascending, slender, and light brown or purplish. The bark on older branches is gray and shreddy. The young twigs have a dense covering of short, soft hairs. The leaves are 1-6 cm (0.4-2.4 in.) long, ovate, and oblong or nearly orbicular in shape with entire or undulate margins, an acute or obtuse apex, and a rounded or slightly acutish base. The leaf surface is dull green, smooth or sparsely hairy on the upper surface, and hairy on the lower surface. The petioles are 2-4 mm (0.08-0.16 in.) long. There are several flowers in densely crowded, short, axillary spikes on the branches of the season. The corolla is broadly bell-shaped, hairy within, pinkish, 3-4 mm (0.12-0.16 in.) long, and turned obliquely upward with lobes about as long as the tube. There are 5 calyx-teeth, each triangular, ciliate, and persistent on the fruit. The fruits are a delicate coral-red (varying to pink) or somewhat purplish color, waxy, ellipsoid, 5-7 mm (0.20-0.28 in.) long, 4-5 mm (0.16-0.20 in.) thick, with beaks about 1 mm (0.04) long (Jones 1940).

There are 3 species of Symphoricarpos in the region and all have roughly similar leaves and growth-form. Symphoricarpos orbiculatus can be distinguished from the others by the smaller flowers (the corolla is less than 5 mm (0.20 in.) long) and the color of the fruits (red vs. white).

  Habitat

Symphoricarpos orbiculatus occurs in a variety of habitats, mostly open, brushy or grassy places in dry, sandy soils. Commonly cited habitats in states to the south and east of Minnesota include stream banks, ravines, pastures, open woods, and prairies.

  Biology / Life History

Symphoricarpos orbiculatus is a long-lived shrub that is known to develop large, dense clones by the growth of rhizomes or "runners" (Stephens 1973). The abundant flowers are produced every year in July, and are apparently pollinated by bees. The seeds are dispersed in the droppings of a variety of animals that eat the fruits, which mature in September and persist until midwinter (Jones 1940). The seeds are reported to germinate in spring of the second or third year after they mature (Hidayati et al. 2001).

The best time to search for S. orbiculatus is when the flowers or fruits are present, from July through the fall.

  Conservation / Management

No conservation or management considerations can be offered until/unless a native population of S. orbiculatus is found to occur in Minnesota.

  Conservation Efforts in Minnesota

Because no extant populations of S. orbiculatus have been found in Minnesota, no conservation efforts have been directed towards this species.

  References

Fernald, M. L. 1950. Gray's manual of botany. Eighth edition. American Book Company, New York, New York. 1632 pp.

Great Plains Flora Association. 1986. Flora of the Great Plains. University Press of Kansas, Lawrence, Kansas. 1,402 pp.

Hidayatl, S. N., J. M. Baskin, and C. C. Baskin. 2001. Dormancy-breaking and germination requirements for seeds of Symphoricarpos orbiculatus (Caprifoliaceae). American Journal of Botany 88(8):1444-1451.

Jones, G. N. 1940. A monograph of the genus Symphoricarpos. Journal of the Arnold Arboretum 21(2):201-252.

Ownbey, G. B., and T. Morley. 1991. Vascular plants of Minnesota: a checklist and atlas. University of Minnesota Press, Minneapolis, Minnesota. 307 pp.

Smith, W. R. 2008. Trees and shrubs of Minnesota. University of Minnesota Press, Minneapolis, Minnesota. 703 pp.

Stephens, H. A. 1973. Woody plants of the North Central Plains. The University Press of Kansas, Lawrence, Kansas. 530 pp.