FLOWERING PLANTS AND FERNS OF ARIZONA 319 



The seeds, usually unnoticed when ripe, are the most reliable evi- 

 dence for positive identification and define the subgeneric groups. 

 Larkspurs in general react readily to variations in soil, shade, and 

 moisture, and numerous natural hybrids are known. The low 

 arenicolous species are spring- or early summer-flowering and occur 

 in large or small colonies. The tall hydrophilous species are summer- 

 and autumn-flowering and occur as close stands in mountain meadows 

 or partially shaded ravines. The plants contain delphinine and 

 other toxic alkaloids. The extent and exact nature of larkspur 

 poisoning is as yet little known; but the tall meadow species are often 

 deadly to cattle, apparently less so to sheep and horses. 



Key to the species 



1. Plants low, less than 70 cm. high, in sandy or heavy soils of plains, deserts, 



and foothills: stems usually not uniformly leafy throughout, the leaves 



clustered at or near the base (2). 



2. Sepals whitish or pale lavender-blue, the spur slender, 15 to 20 mm. long; 



lower petals white, conspicuously white-pilose, deeply notched at apex 



into cuneate-acuminate lobes, the sinus 4 to 6 mm. deep; stems puberu- 



lent with fine curling white hairs 1 1. D. wootoxi. 



2. Sepals azure blue to intense royal blue, the spur 10 to 12 (or 15) mm. long; 

 lower petals bluish to dark purple, shallowly to deeply notched into 

 ovate lobes, the sinus not more than 4 mm. deep: stems glabrous, often 

 glaucous, rarelv glandular-hairv, but not closely and evenlv puberulent 

 (3). 

 3. Sinuses of the lower petals 3 to 4 mm. deep; leaves chiefly strictly basal, 

 the primary segments obovate or even subspatulate: flowers mostly 



clear dark or royal blue 2. D. scaposum. 



3. Sinuses of the lower petals less than 2.5 mm. deep: leaves not strictly 



basal, the primary segments linear to broadly cuneate-oblanceolate; 



flowers blue purple to pale or azure blue (4). 



4. Steins narrowing at ground level, easily disarticulating from the tuberous 



roots: flowers dark blue, the upper petals bicolored, prominently 



venulose; plant of pine forests 3. D. pixetorum. 



4. Stems not narrowing at ground level, persistent upon the woody- 

 fibrous roots; flowers variously light blue, the upper petals pallid 

 or, if somewhat bicolored, then not conspicuously venulose: plants 



of canyons and deserts 4. D. amabile. 



1. Plants tall, usually 1 m. or more high, in heavy often wet soils of ravines, 



meadows, and valley floors: stems usually leafy throughout; flowers 



dark blue or purple (5). 



5. Racemes dense, numerously flowered: leaves nearly circular in outline, 4 to 



7 cm. wide, the primary segments cuneate-obovate with short barely 



acute teeth, velvety with gray puberulence beneath. 



5. D. GERAXIIFOLIFM. 



5. Racemes more or less loose or elongating early; leaves pentagonal in outline, 

 10 to 18 (or 20) cm. wide, glabrous or thinly hairy (6). 

 6. Sepals lance-acuminate; rachis of the raceme lustrous-hairy with glandular 

 spreading hair-; follicles subglabrous, dark-venulose_ 6. D. barbeyi. 

 6. Sepals ovate; rachis nonglandular; follicles ashv-puberulent, not venulose 

 (7). 

 7. Primary segments of the leaves cuneate-rhomboid or cuneate-obovate, 

 the intersegmental spaces prominent, the ultimate divisions pin- 

 natifid with long sublinear few-toothed pinnae, the teeth acute; 

 stems puberulent with a close even hairiness 7. D. andesicola. 

 7. Primary segments of the leaves cuneate-obovate, the intersegmental 

 spaces scant, the ultimate divisions lacerate-pinnatind with short 

 oblong pinnae, the teeth subobtuse or abruptly acute; stems sub- 

 glabrous below 8. D. S1ERKAE-HLANTAE. 



1. Delphinium wootoni Rydb., Torrey Bot. Club Bui. 26: 587. 18 



Pinaleno, Chiricahua, Huachuca, Tumacacori, and Rincon moun- 

 tains and adjacent valleys (Graham, Cochise, Santa Cruz, and Pima 



