FLOWERING PLANTS AND FERNS OF ARIZONA 643 



Key to the species 

 1. Leaves elongate, linear, parallel-veined, usually entire. 



1. E. SPARGAXOPHYLLUM. 



1. Leaves shorter, lanceolate to oblanceolate, reticulate- veined, crenate to 

 spinose-serrate or pinnatifid (2). 

 2. Basal leaves obscurely crenate or serrate, not spinose; heads cylindric-ovoid, 



amethystine 2. E. phyteumae. 



2. Basal leaves spinose-serrate or pinnatifid; heads ovoid, not amethystine (3). 



3. Plants from a cylindric taproot; lower cauline leaves pinnatifid to bipin- 



natisect; inflorescence paniculately branched, the heads comate; 



bracts linear-lanceolate to lanceolate, entire or with 1 or 2 pairs of 



lateral spines near the middle, yellowish above. 



3. E. HETEROPHYLLUM. 



3. Plants from a fascicle of fibrous or fleshy roots; lower cauline leaves 

 spinose-serrate; inflorescence successively trifurcate, the heads not 

 comate; bracts broadly lanceolate to oblanceolate, spinose-serrate 

 with 2 or 3 pairs of teeth, silvery-white above 4. E. lemmoni. 



1. Eryngium sparganophvllum Hemsl. in Hook., Icon. PL 26: pi. 



2508. 1897. 

 Agua Caliente ranch near Tucson, 2,900 feet, marshy ground 

 (Shreve in 1908). New Mexico to southern Arizona and Mexico. 



2. Eryngium phyteumae Delar., Eryng. 51. 1808. 



Eryngium discolor S. Wats., Amer. Acad. Arts and Sci. Proc. 

 18: 193. 1883. 



In water, Huachuca Mountains, Cochise County (Lemmon 1714, 

 2714). Southeastern Arizona and Mexico. 



3. Eryngium heterophyllum Engehn. in Wisliz., Mem. North. Mex. 



106. 1848. 



Eryngium wrightii A. Gray, PL Wright. 1: 78. 1852. 



Cochise and Santa Cruz Counties, 4,000 to 6,500 feet, plains and 

 along watercourses. Texas to southeastern Arizona and Mexico. 

 Known locally as Mexican-thistle. The flowers are pale blue. 



4. Eryngium lemmoni Coult. and Rose, Bot. Gaz. 14: 279. 1889. 

 Cochise County, chiefly in the Chiricahua and Huachuca Moun- 

 tains, 6,000 to 7,000 feet, type from the Chiricahua Mountains 

 (Lemmon 17). Southeastern Arizona and northern Mexico. 



4. OSMORHIZA. Sweetroot, sweet-cicely 



Plants perennial, caulescent, glabrous to hirsute; leaves biternate or 

 ternate-pinnate, the leaflets broad, variously toothed or lobed, dis- 

 tinct; peduncles exceeding the leaves; umbels compound; involucre 

 usually absent; calyx teeth obsolete; corolla white to greenish yellow; 

 stylopodium conic; fruit linear to linear-oblong, 10 to 20 mm. long, 

 cylindric or clavate, more or less attenuate at base, slightly com- 

 pressed laterally or not at all, the ribs inconspicuous, the oO. tubes 

 obsolete in mature fruit, the seed face sulcate. 



Key to the species 



1. Involucels of several bractlets 1. O. brachypoda. 



1. Involucels absent (2). 



2. Ravs and pedicels spreading-ascending; fruit linear-oblong, cvlindric. 



* 2. O. XUDA. 



2. Rays and pedicels divaricate; fruit clavate __ 3. O. obtusa. 



