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



mostly pedicellate with pedicels of different lengths, forming close 

 or loose cymose inflorescences; calyx enclosing the corolla tube; 

 corolla lobes mostly spreading to reflexed and equaling the tube; 

 anthers oval, on sbort filaments; scales oblong, shallowly fringed, 

 free from the corolla tube at the upper end only. 



7. Cuscuta denticulata Engelm., Amer. Nat. 9: 348. 1875. 



Hope, Yuma County {Fulton 8508), nearTopock and Boulder Dam, 

 Mohave County, where apparently not uncommon {Clover 4177 ', Peebles 

 and Parker 14780, 14793). Southern Utah to southern California and 

 western Arizona. 



Host plants of this species include Coleogyne, Larrea, Gutierrezia, 

 Chrysothamnus, and Hymenoclea, but Arizona specimens have been 

 collected only on Larrea. Stems very slender; flowers small, mostly 

 in 2- or 3-flowered clusters; calyx yellow and more or less glistening in 

 dry specimens, with large and conspicuous cells, almost enclosing the 

 corolla tube; corolla becoming urceolate, the lobes oval-oblong, com- 

 monly obtuse; scales about reaching the anthers, oblong, denticulate; 

 embryo with an enlarged globose, knoblike end, a character found 

 otherwise only in the closely allied C. veatchii of Baja California. 



8. Cuscuta gronovii Willd. ex Roem. and Schult., Syst. Veg. 6: 205. 



1820. 



Grand Canyon, Coconino County {Eggert in 1886). Eastern and 

 central United States, where this is the commonest species of dodder, 

 to northern Arizona. 



It occurs on a very wide range of both woody and herbaceous hosts 

 with no apparent preference. Flowers 2 to 4 mm. long, in loose or 

 somewhat dense, paniculate cymes; calyx mostly shorter than the 

 corolla tube; corolla lobes spreading to reflexed, shorter than the 

 campanulate tube; scales commonly oblong, about reaching the 

 stamens; styles commonly about equaling the ovary; capsule en- 

 veloped by the withered corolla. 



9. Cuscuta mitraeformis Engelm. ex Hemsl., Diagn. PL Mex. 54. 1880. 

 Cave Creek, Chiricahua Mountains, Cochise County {Kearney and 



Harrison 6176), about 6,000 feet, on Lupinus. Southeastern Arizona 

 and Mexico. 



Stems coarse; flowers on short pedicels, forming compact, globular 

 clusters; calyx lobes about as long as the corolla tube, ovate, obtuse, 

 more or less unequal, ii regular, the larger lobes often strongly and 

 unevenly carinate; corolla lobes ovate, obtuse, about as long as or 

 exceeding the campanulate tube; scales oblong, mostly somewhat 

 truncate and bifid, or less commonly ovate, as long as the tube, and 

 deeply fringed; styles shorter than the conic ovary, becoming widely 

 divergent; capsule 5 to 8 mm. long, enveloped by the withered corolla. 



10. Cuscuta erosa Yuncker, 111. Univ. Biol. Monog. 6: 116. 1921. 

 Mountains of Pima County. Southern Arizona and northern 



Sonora. 



Host plants include Amaranthus, Ipomoea, Siphonoglossa, Anisacan- 

 thus, and Franseria. Pedicels mostly shorter than the flowers; 

 calyx lobes orbicular, membranaceous, denticulate on the margin, 

 fleshier in the median part, nearly distinct; corolla lobes erect to 

 reflexed, about as long as or slightly shorter than the campanulate 

 tube, ovate-oblong, obtuse; scales broad, fringed, about equaling the 



