Cornus alternifolia

Cornus alternifolia

Languages: English

Overview

Brief Summary

The Alternate-leafed (or Pagoda) Dogwood (Cornus alternifolia) is a shrub or small tree with leaves that are 5 to 13 cm in length, alternately arranged, and often crowded toward the tips of greenish twigs (some leaves may be oppositely arranged or whorled). The leaves are conspicuously acuminate (i.e., tapered to a narrow tip) with 4 to 5 veins to each side of the midrib. Petioles (leaf stalks) may range from 8 to 50 mm even on a single twig. The pith is white. Buds have two scales and leaf scars are narrow and raised, with three bundle scars. Maximum tree height is around 6 to 7 m. Flowers, which appear in late spring after the leaves, are small and white and borne in flat-topped clusters 4 to 6 cm across (Choukas-Bradley and Alexander 1987). The blue-black fruits are clustered at the ends of twigs and have red stems. Cornus alternifolia is found in eastern North America from Newfoundland and Nova Scotia to Minnesota and south to Florida, Alabama, and Arkansas and is often found growing in rich woods and thickets. The insect-pollinated flowers attract a variety of butterflies and bees. The fruits are eaten by many birds, including Ruffed Grouse, and the twigs are browsed by deer and rabbits. (Petrides 1988; Gleason and Cronquist 1991)

According to molecular phylogenetic analyses by Fan and Xiang (2001) and Xiang et al. (2006), the sister species to the North American C. alternifolia is the Asian species C. controversa, a finding that is consistent with a range of similarities. These two species are the only extant Cornus with alternately arranged leaves (although even in these species the leaves are often in subopposite pairs or, at the ends of branches, crowded almost into whorls). In addition, they are the only two species whose fruits consistently have stones with deep pits in their apices (C. controversa with a small deep pit and C. alternifolia with a large one) and both have a derived chromosome number (2n=20 rather than the typical 22; Gleason and Cronquist 1991) and lack rudimentary inflorescence bracts as well as extra seed chambers. (Eyde 1988) In addition to these morphological and cytological similarities, C. alternifolia and C. controversa also have similar anthocyanin profiles (Vareed et al. 2006).

Vareed et al. (2006) analyzed the anthocyanins present in the fruits of C. alternifolia and several other Cornus species, quantifying them using HPLC, characterizing them using spectroscopic methods, and screening their biological activity using several different assays. Results suggested potential anti-tumor activity for C. alternifolia fruits.

Author(s): Shapiro, Leo
Rights holder(s): Shapiro, Leo

References

Choukas-Bradley, M., & Alexander P. (1987).  City of Trees: The Complete Field Guide to the Trees of Washington, D.C., revised edition. Baltimore, Maryland: Johns Hopkins University Press.
Eyde, R. H. (1988).  Comprehending Cornus: Puzzles and Progress in the Systematics of the Dogwoods. Botanical Review. 54, 233-351.
Fan, C., & Xiang Q. - Y. (2001).  Phylogenetic Relationships within Cornus (Cornaceae) Based on 26S rDNA Sequences. American Journal of Botany. 88, 1131-1138.
Gleason, H. A., & Cronquist A. (1991).  Manual of Vascular Plants of Northeastern United States and Adjacent Canada, 2nd edition. New York: The New York Botanical Garden.
Petrides, G. A. (1988).  A Field Guide to Eastern Trees. Boston: Houghton Mifflin.
Vareed, S. K., Reddy M. K., Schutzki R. E., & Nair M. G. (2006).  Anthocyanins in Cornus alternifolia, Cornus controversa, Cornus kousa and Cornus florida fruits with health benefits. Life Sciences. 78, 777-784.
Xiang, Q. - Y., Thomas D. T., Zhang W., Manchester S. R., & Murrell Z. (2006).  Species level phylogeny of the genus Cornus (Cornaceae) based on molecular and morphological evidence—implications for taxonomy and Tertiary intercontinental migration. Taxon. 55, 9-30.