WILSON. GENERA OF ARALES THE GENERA OF THE ARALES IN THE SOUTHEASTERN SNITEI) STATES I KENNETH A. WILSON THE ARALES (Spathiflorae), in the view of most authors, include only the families Araceae and Lemnaceae, the latter representing highly re-duced plants of aroid ancestry. A much broader interpretation of the order is the one of Wettstein, who included in his "Spadiciflorae" not only the Araceae and Lemnaceae, but also the Palmae and Cyclanthaceae. Other authors (e.g., K. Fritsch. Ber. Deutsch. Bot. Ges. 50a: 162-184. 1932) have interpreted this group as including also the families Pandanaceae, Sparganiaceae, and Typhaceae. Such an interpretation of the order is subject to considerable disagreement, and these families may indeed not be very closely related to each other. The Arales are here interpreted in the Englerian sense to include only the families Araceae and Lemnaceae, which are generally agreed to be closely allied. ARACEAE (ARUM FAMILY) Tuberous or rhizomatous, terrestrial or aquatic (rarely floating) herbswith watery, milky or acrid sap. Leaves simple or compound, basal andsolitary or clustered, or cauline and alternate. Inflorescence a spadix (anaxis with small, sessile, tightly grouped flowers), subtended by an her-baceous spathe (or spathe absent). Flowers bisexual, with a perianth (inours), or unisexual, without a perianth (the plants then monoecious ordioecious); perianth, when present, of 2-6 parts; stamens 1-6, free orunited into a synandrium; gynoecium completely syncarpous, the ovaryl(-many)-locular, superior or inferior (i.e., embedded in the spadix);ovules 1-many in each locule. Fruit usually a berry. Seeds with or withoutendosperm, the embryo large. (Including Pistiaceae.) A large family, primarily tropical or subtropical in its distribution, ofover 100 genera grouped into eight subfamilies by Engler (18 tribes by 1Prepared for a biologically oriented generic flora of the southeastern United States,a joint project of the Arnold Arboretum and the Gray Herbarium made possiblethrough the support of George R. Cooley and the National Science Foundation, andunder the direction of Reed C. Rollins and Carroll E. Wood, Jr. The scheme followsthat outlined at the beginning of the series (Jour. Arnold Arb. 39: 296-346. 1958).Other published portions of these studies will be found in Jour. Arnold Arb. 40: 94-112, 161-171, 268-288, 369-384, 391-397, 413-419. 1959, and in the present issue. Inconnection with the treatments of the Araceae and the Lemnaceae, I am particularlyindebted to Carroll E. Wood, Jr., for his valuable suggestions, advice, and information.The illustrations are the skillful work of Dorothy H. Marsh, and are based on mate-rial collected by Carroll E. Wood, Jr., and Richard J. Eaton. I wish also to expressmy indebtedness to R. B. Channell, George R. Cooley, Joseph Ewan, R. K. Godfrey,H. F. L. Rock, and Edward G. Voss, who kindly assisted in supplying information,aided in the obtaining of specimens, and helped in various other ways.1960]
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