FLOWERING PLANTS AND FERNS OF ARIZONA 259 



13. Inflorescences erect or nearly so (14). 



14. Leaf blades glabrous, or strigose beneath; perianth usually 



bright pink 13. P. penxsylvanicum. 



14. Leaf blades floccose-tomentose beneath; perianth pale pink. 



14. P. INCANUM. 

 12. Sheaths with marginal bristles, these sometimes almost wanting in 

 P. fusiforme (15). 

 15. Inflorescences loose, more or less interrupted, narrowly cylindric; 



perianth greenish, glandular-punctate 15. P. punctatum. 



15. Inflorescences dense, usually not interrupted; perianth pink, not 

 or very obscurely glandular (16). 

 16. Internodes normally fusiform-inflated; inflorescences commonly 

 more than 3 cm. long, narrowly cylindric, not more than 6 



mm. wide 16. P. fusiforme. 



16. Internodes not normally inflated; inflorescences commonly less 

 than 3 cm. long, broadly cylindric or somewhat ovoid, usually 

 more than 6 mm. wide 17. P. persicaria. 



1. Polygonum convolvulus L., Sp. PL 364. 1753. 



Bilderdykia convolvulus Dum., Fl. Belg. 18. 1827. 



Coconino, Yavapai, Gila, and Cochise Counties, 5,000 to 8,000 feet, 

 roadsides, etc., July and August. Widely distributed in the United 

 States; naturalized from Eurasia, 



Cornbind. The only climbing plant of this family in Arizona. 



2. Polygonum watsoni Small, Columbia Univ. Dept. Bot. Mem. 1: 



138. 1895. 

 Kaibab Plateau, Coconino County, 9,000 feet {Mead 967), August. 

 Saskatchewan to British Columbia, south to New Mexico, northern 

 Arizona, and California. 



3. Polygonum argyrocoleon Steud. ex Kunze, Linnaea 20: 17. 1847. 

 Mohave, Maricopa, Pinal, and Yuma Counties, 100 to 3,500 feet, 



roadsides, April to October. Arizona and California; naturalized 

 from central Asia. 



The plant resembles P. ramosissimum Michx.,but the inflorescences 

 are more spicate. 



4. Polygonum aviculare L., Sp. PI. 362. 1753. 



Navajo and Coconino Counties to Maricopa, Pinal, and Cochise 

 Counties, 1,000 to 8,000 feet, roadsides, April to October. Widely 

 distributed in North America; naturalized from Eurasia, 



The writers are unable to make any satisfactory distinction between 

 P. buxiforme Small and P. aviculare. Some of the Arizona specimens 

 referred to the latter may belong to P. neglectum Besser, a very similar 

 Old World species that has also become naturalized in the United 

 States. 



5. Polygonum douglasii Greene, Calif. Acad. Sci. Bui. 1: 125. 1885. 

 Apache, Coconino, and Graham Counties, 7,000 to 9,500 feet, June 



to September. Saskatchewan to British Columbia, south to New 

 Mexico, Arizona, and California, 



6. Polygonum sawatchense Small, Torrev Bot, Club Bui. 20: 213. 



1893. 

 Apache County to Mohave County, south to Cochise and Pima 

 Counties, 5,500 to 8,000 feet, common in dry pine woods, June to 

 September. South Dakota to Washington, New Mexico, Arizona, 

 and California. 



