FLOWERING PLANTS AND FERNS OF ARIZONA 647 



12. PERIDERIDIA 



Plants perennial from fascicled tuberous or fusiform roots, usually 

 caulescent, glabrous; leaves mostly pinnate or ternate-p innate, the 

 leaflets filiform to lanceolate; peduncles exceeding the leaves; umbels 

 compound; involucre usually absent; involucel present, the bractlets 

 linear to lanceolate; calyx teeth prominent; corolla white or pink; 

 stylopodium conic; fruit orbicular to oblong, 2 to 4 mm. long, later- 

 ally compressed, the ribs inconspicuous, the oil tubes 1 to 5 in the 

 intervals, 2 to 8 on the commissure, the seed face plane to broadly 

 concave. 



Key to the species 



1. Leaves pinnate to bipinnate; bractlets of the involucel linear-acuminate; fruit 

 orbicular to suborbicular, 2 to 3 mm. long, the oil tubes solitary in the 

 intervals 1. P. gairdxeri. 



1. Leaves ternate, rarely biternate, the uppermost entire; bractlets of the in- 

 volucel narrowly lanceolate; fruit ovoid to oblong, 3 to 4 mm. long, the 

 oil tubes 2 to 4 in the intervals 2. P. parishii. 



1. Perideridia gairdneri (Hook, and Arn.) Mathias, Brittonia 2: 244. 



1936. 



Atenia gairdneri Hook, and Arn., Bot. Beechey Voy. 349. 



1840. 

 Carum gairdneri A. Gray, Amer. Acad. Arts and Sci. Proc. 7: 



344. 1867. 



White Mountains (Apache County), Flagstaff, Mogollon Escarp- 

 ment, and Bill Williams Mountain (Coconino County), 7,000 feet or 

 higher, moist soil. South Dakota to New Mexico, west to British 

 Columbia and southern California. 



Yampa, wild-caraway. The tuberous roots have a pleasant nutty 

 flavor and were used by the Indians as food. The seeds were used as 

 seasoning. 



2. Perideridia parishii (Coult. and Rose) Nels. and Macbr., Bot. Gaz. 



61:33. 1916. 



Pimpinella parishii Coult. and Rose, Bot. Gaz. 12: 157. 1887. 

 Eulophus parishii Coult. and Rose, Rev. North Amer. Umbell. 



112. 1888. # 

 Eulophus parishii var. rusbyi Coult. and Rose, Bot. Gaz. 14: 



281. 1889. 



North rim of the Grand Canyon to Oak Creek, Coconino County, 

 6,500 to 8,000 feet, moist soil in pine woods, July. Northern Arizona, 

 California, and Nevada. 



Aletes acavlis (Torr.) Coult. and Rose. Ranges in the Rocky Mountains from 

 Colorado to New Mexico and western Texas. In the herbarium of the University 

 of California there is a specimen of this species bearing the label "Gila River" 

 and collected by Mohr. This is probably an error, since Dr. Mohr collected the 

 same species in Colorado. 



13. SIUM. Waterparsnip 



Plants perennial from fascicled fibrous roots, caulescent, aquatic, 

 glabrous; leaves simply pinnate, the leaflets lanceolate to linear, finely 

 to coarsely serrate or incised, mostly acute; peduncles exceeding the 

 leaves; umbels compound; involucre of 6 to 10 unequal, lanceolate or 

 linear bracts, these reflexed in fruit ; involucel of 4 to 8 linear-lanceolate 

 bractlets, these shorter than the flowers; calyx teeth minute; corolla 



