Upper Canopy Collection and Identification ofGrapevines (Vitis) from Selected Forests in theSoutheastern United States

Woody grapevines (Vitis spp.) are common in the deciduous forests of the southeastern United States. Their growth habit makes leaf collection challenging and polymorphic leaves make identification of species difficult. Mature grapevines can grow up to 48 cm in diameter at breast height and reach the upper canopy of trees more than 35 m in height. Leaf morphology is the most readily available character used for species identification. However, most mature grapevines do not produce leaves below the upper canopy and if they do, these leaves are morphologically indistinguishable from other species. In order to sample leaves from mature grapevines, the doubled rope climbing method was used to access the canopy in Great Smoky Mountains National Park in Tennessee, Daniel Boone National Forest and Berea College Forest in Kentucky, and Ha Ha Tonka State Park in Missouri. Leaf voucher specimens were collected from the upper canopy and used to create a modified key to species for those regions. The purposes of this paper are to report a new method for collecting grapevine leaf vouchers from the upper canopy of trees, to present a modified key used for identifying dried leaf vouchers of Vitis species, and to present a discussion of the possible utility of this research for future studies. INTRODUCTION Grapevines (Vitis L.) are in the order Rhamnales in the family Vitaceae. Grapevines are dicotyledonous, deciduous, perennial plants that can live for many years and can grow more than 35 m tall when supported by an adjacent tree. A grapevine is a liana (woody climber) that climbs by wrapping long thin tendrils around a support. Grapevines develop woody, flaky bark as they get older. The flowers are dioecious, greenish, and borne only on new shoots that arise from dormant buds formed on the previous season’s growth. They are also polygamodioecious, which means that they are essentially dioecious, but also having some bisexual flowers present in some or all plants. Consequently, both flower sexes are needed for precise species identification (Moore 1985). The genus Vitis is made up of species predominantly found in the temperate regions of the Northern Hemisphere, including North America and Asia, and a few species in the tropics (Gleason and Cronquist 1991). There are approximately 60 species of Vitis naturally occurring in the United States, with V. aestivalis, V. cinerea, and V. vulpina as the most commonly occurring in the southeastern United States (Stupka 1964, Jones 2005). The fruit of several Vitis species, including V. vinifera, V. labrusca, V. aestivalis, V. rotundifolia, and their hybrids, have been cultivated for commercial production in vineyards for consumption as fresh table grapes, dried as raisins, produced into juices, and for fermentation into wine (This et al. 2006). Grape leaves are considered edible and are used in the production of dolmades (stuffed grapevine leaves). Native North American grapes have been important to the grape production industry worldwide since the late 1800’s when the indigenous phylloxera root louse (Daktulo*email address: [email protected] Present address: Department of Plant Pathology, University of Georgia, 2105 Miller Plant Science Building, Athens,