698 MISC. PUBLICATION 42 3, IT. S. DEPT. OF AGRICULTURE 



1. Pherotrichis schaffneri A. Gray, Syn. Fl. ed. 2, 2 1 : 462. 1886. 



Huachuca Mountains, Cochise County (Lemmon 2816), September. 

 Southern Arizona and northern Mexico. 



12. LACHNOSTOMA 



Stems twining; leaves opposite, petioled, the blades triangular- 

 ovate; inflorescences lateral, few-flowered; corolla whitish, conspic- 

 uously reticulate with green veins, cleft about halfway, the lobes 

 oblong-ovate, the tube retrorsely villous within; stigma depressed, 

 not surpassing the stamens, with a broad 5-angled disk; pods large, 

 lance-ovate in outline, strongly angled and finely ridged longitudinally. 



1. Lachnostoma arizonicum A. Gray, Amer. Acad. Arts and Sci. Proc. 

 20: 296. 1885. 

 Kincon, Santa Catalina, and Baboquivari Mountains (Pima 

 County), 3,500 to 4,500 feet, along streams in canyons, May to August, 

 type from the Santa Catalina Mountains (Lemmon). Known only 

 from southern Arizona. 



Rothrockia cordifolia A. Gray has been attributed to Arizona, apparently by 

 confusion with Lachnostoma arizonicum, from which it may be distinguished by 

 the larger, much more deeply cleft corolla, this glabrous within and not conspicu- 

 ously veined, the elevated stigma much surpassing the stamens, and the smooth 

 pods. It occurs in Sonora not far from the southern boundary of Arizona. 



103. CONVOLVULACEAE. Convolvulus family 



Plants herbaceous or suffrutescent, mostly with twining or trailing 

 stems, in one genus without chlorophyll and parasitic ; leaves alternate, 

 simple but sometimes deeply lobed or parted, in 1 genus reduced to 

 minute scales; flowers perfect, regular, mostly 5-merous, often showy, 

 axillary, solitary or in cymes, the peduncle jointed; pistil of 2 united 

 or separate carpels, the styles 1 or 2, often cleft; fruit a capsule, de- 

 hiscent or indehiscent. 



The morning-glories and other favorite ornamentals belong to this 

 family, of which the most important member, economically, is the 

 sweetpotato (Ipomoea batatas Poir.). 



Key to the genera 



1. Plants without green coloring matter, parasitic on the stems of various hosts; 

 stems twining; leaves reduced to small scales; flowers small; corolla white 

 or whitish, usually with fimbriate or dentate appendages within. 



1. CUSCUTA. 



1. Plants with green coloring matter, autophytic; leaves with well-developed 

 blades (2). 

 2. Ovary deeply 2-lobed; styles 2; stems creeping, rooting at the nodes; leaf 

 blades reniform, wider than long; flowers solitary, small and incon- 

 spicuous; pedicels after anthesis often strongly re volute or sigmoid- 



curved 2. Dichondra. 



2. Ovary not lobed (3). 



3. Corolla imbricate in the bud, white; styles 2, entire; stigmas capitate. 



4. Cressa. 

 3. Corolla plicate-convolute in the bud (4). 



4. Styles 2, separate to the base or nearly so, each 2-cleft; stigmas linear- 

 filiform or slender-clavate; stems not twining; corolla rotate- 



campanulate or broadly f unnelform 3. E volvulus. 



4. Style 1 or, if 2-cleft, then the divisions entire (5). 



5. Stigma 1, globose or nearly so, entire or lobed 7. Ipomoea. 



