PORTER, GENERA OF ZYGOPHYLLACEAE THE GENERA OF ZYGOPHYLLACEAE IN THE SOUTHEASTERN UNITED STATES 1 DUNCAN M. PORTERZYGOPHYLLACEAE R. Brown in Flinders, Voy. Terra Austral. 2: 545. 1814, "Zygophylleae" (BEAN-CAPER FAMILY) Annual to perennial [often suffrutescent] herbs [shrubs] or occasionallytrees; branches usually divaricate, with angled or swollen nodes, growthsympodial. Iiaves opposite [occasionally alternate], even-pinnatelycompound, [sometimes odd pinnate, occasionally simple or 2-foliolate,rarely 3-7-foliolate], often fleshy to coriaceous, persistent, petiolate [tosubsessile]; leaflets entire [sometimes lobed], inequilateral, petiolulate tosubessile; stipules paired, free, foliaceous [sometimes fleshy or spinescent],persistent or rarely deciduous to caducous. Flowers [4] 5 [6] -merous, per-fect, hypogynous, regular or occasionally slightly irregular; pedunclesterminal or pseudaxillary, 1-flowered, solitary or occasionally few to many.Sepals [4] 5 [6], free or rarely slightly connate basally, imbricate inbud, persistent or occasionally deciduous. Petals as many as sepals, free[rarely connate basally], often clawed, sometimes twisted, imbricate orconvolute, deciduous, rarely marcescent. Extrastaminal and/or intrastam-inal glandular disc usually present and conspicuous. Stamens in [1] 2[or 3] whorls of 5 each, outer[most] whorl usually opposite petals, oftenalternately unequal in length or sterile; filaments free, subulate to filiform[rarely winged], frequently glandular [or appendaged] basally, outerwhorl occasionally adnate basally to petals, inserted on or below disc; an-thers 2-loculate, subbasifixed to versatile, introrse, longitudinally dehiscent.Gynoecium [2-]5-carpellate, syncarpous; style terminal, usually simple; 'This treatment was prepared for a generic flora of the southeastern United States,a joint project of the Arnold Arboretum and the Gray Herbarium of Harvard Uni-versity made possible through the support of the National Science Foundation (GrantGB-6459X, principal investigator, C. E. Wood, Jr.). The format is that established inthe first paper in the series (Jour. Arnold Arb. 39: 296-346. 1958). The area coveredincludes North and South Carolina, Georgia, Florida, Tennessee, Alabama, Mississippi,Arkansas, and Louisiana. The descriptions are based primarily on the plants of thisarea, with additional material from extraterritorial taxa in brackets. References thatI have not seen are marked by an asterisk. I am very grateful to Dr. Wood for his numerous suggestions and additions, to Mrs.Nancy Dunkly for the preparation of the typescript, and to both for their help in re-checking many of the included references at a time of transition when much of thelibray of my own institution was not available for consultation. The illustration byArnold D. Clapman was drawn from materials collected by Dr. Wood, who also madethe dissections.
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