642 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



Key to the species 



1. Leaves peltate, orbicular, shallowly 8- to 13-lobed; inflorescence an interrupted 

 simple or branched spike, longer than the leaves, the flowers borne in 

 scattered verticils 1. H. verticillata. 



1. Leaves not peltate, roundish-reniform, 5- or 6-lobed to about the middle; 

 inflorescence a simple umbel; peduncles shorter than the leaves. 



2. H. RANUNCULOIDES. 



1. Hydrocotyle verticillata Thunb., Diss. Hydroc 2, 5. 1798. 



Hydrocotyle cuneata Coult. and Rose, Contrib. U. S. Natl. 

 Herbarium 7: 28. 1900. 



Montezuma Well, Yavapai County (MacDougal 575, the type of 

 H. cuneata), Catalpa, Gila County (MacDougal in 1891), San Bernar- 

 dino Ranch, Cochise County (Mearns 829), Sonoita Valley, Santa 

 Cruz County (Lemmon 2710). Massachusetts to Florida and the West 

 Indies, west to southern Utah, Arizona, and California. 



In the typical form the inflorescence is often bifurcate and the fruit 

 sessile or subsessile. The var. racemosa (Sesse and Moc.) Mathias, 

 distinguished from the species by a rarely bifurcate inflorescence and 

 pedicellate fruit with pedicels up to 10 mm. long, has been collected 

 at Beaver Dam, Mohave County (Jones 5024), and near Tucson, 

 Pima County (Pringle in 1881, Dewey in 1891). 



2. Hydrocotyle ranunculoides L. f., Sup. 177. 1781. 



San Pedro River valley, Cochise County (Tourney in 1894), Tucson 

 (Tourney in 1894). Pennsylvania and Delaware to Florida, west to 

 Washington and Arizona, south to tropical America. 



2. BOWLESIA 



Plants annual, stellate-pubescent, prostrate or suberect, dichot- 

 omously branching; leaf blades suborbicular, palmately 5- to 7-lobed; 

 peduncles axillary, shorter than the leaves; umbels simple, few- 

 flowered; involucral bracts small; calyx teeth prominent; corolla 

 greenish white; stylopodium depressed-conic; fruit broadly ovate, 1 to 

 1.5 mm. long, stellate-pubescent, turgid, narrowed at the commissure, 

 the ribs and oil tubes obsolete, the seed face plane or convex. 



1. Bowlesia incana Ruiz and Pavon, Fl. Peruv. Chil. 3: 28. 1802. 



Bowlesia septentrionalis Coult. and Rose, Contrib. U. S. Natl. 

 Herbarium 7:31. 1900. 



Mohave County to Graham, Pima, and (probably) Yuma Coun- 

 ties, 1,000 to 3,500 feet, common, usually among bushes, spring, type 

 of B. septentrionalis from near Tucson (Zuck). Southern Texas to 

 Arizona and central California; Peru. 



3. ERYNGIUM. Eryngo, button-snakeroot 



Plants perennial, caulescent, glabrous; stems simple or branched; 

 leaf blades lanceolate to oblanceolate and reticulate-veined, or linear 

 and parallel- veined, entire to pinnatifid; peduncles exceeding the 

 leaves; inflorescence a dense bracteate head; bracts linear to ovate- 

 lanceolate, entire to spinulose-serrate ; floral bractlets usually entire; 

 calyx lobes lanceolate to ovate, obtuse or acute; corolla white or blue; 

 stylopodium absent; fruit ovoid, flattened laterally, covered with 

 hyaline scales or tubercles, the ribs obsolete, the oil tubes several, 

 inconspicuous, the seed face plane. 



