The Genera of Convolvulaceae in the Southeastern United States

Abstract

CONVOL\-ULACEAE Jussieu ( Morxixg-glory Family)Annual or perennial herbs or woody plants, climbing or prostrate, rarely erect |or shrubby (more rarely trees)] without tendrils, the stem usually twining and with milky sap.Leaves alternate, simple, without stipules, rarely reduced to scales {Cuscuta).Flowers solitary or in cymes subtended by two opposite or subopposite bracts.Sepals S [rarely 4] free (rarely united at the base), imbricate.Corolla sympetalous, entire, 5lobed or S-parted [rarely 4], induplicate-valvate or contorted in bud.Stamens 5 (rarely fewer), inserted on the corolla tube, alternate with the corolla lobes; pollen spherical and spinulose, or spherical and smooth, or ellipsoid with parallel folds.Gynoecium syncarpous, the style solitary and simple or forked, or styles 2 (rarely 3 or 4), the ovary superior, 2-or U locular or at times subdivided by false partitions into 4 locules, rarely 3locular.Ovules erect, anatropous, sessile, 2 in each locule (rarely sohtary).Fruit a capsule, 2-or 3-locular with 1 or 2 seeds in each locule, usually dehiscing by valves or circumscissile, irregularly dehiscent, or indehiscent.Embryo straight, cotyledons folded or spirally coiled, rarely small or A world-wide family, primarily of the tropics and subtropics, but extending also into the temperate regions, and best represented in Asia and the Americas.Characterized by the presence of milky sap, bicollateral vascular bundles, plaited corollas, axile placentation, basal erect ovules, and folded cotyledons, the family consists of about 50 genera and 2000 species and is represented in our area by 10 genera.On the basis of the structure of the pollen grains Hallier divided the family into two groups, the Psiloconiae with smooth pollen and the Echinoconiae with spinulose pollen (rank not designated) and into nine ^Prepared for a biologically oriented generic flora of the southeastern United States, a joint project of the Gray Herbarium and the Arnold Arboretum made possU ble through the support of George R. Cooley and the National Science Foundation, and under the direction of Reed C. Rollins and Carroll E. Wood, Jr.The scheme follows that outlined at the beginning of the series (Jour.Arnold .A.rb.39: 296-346.40, 4L 1959Arnold .A.rb.39: 296-346.40, 4L , 1960. .The area covered in this, as in former treatments, is bounded by and includes North Carolina, Tennessee, .Arkansas,