184 KEY AND FLORA 



a. A. discoi'dea Benth. Heads without rays in a hractless panicle. 

 Involucre hairy and glandular. Leaves ovate or oblong, irregularly 

 toothed, the upper sessile and often alternate. Akenes becoming 

 smooth, not glandular. In the Coast Mountains. 



h. A. cordifo'lia Hook. Heads icith conspicuous rays, usually about 

 ^ in. long (rarely rayless). Leaves opposite, 2 pjairs on the stem; 

 root leaves roundish and deeply cordate, coarsely toothed. In the 

 Sierra Xevada Mountains. 



c. A. folio'sa Nutt. Perennial, from rootstocks. Stems erect, 

 leafy, clothed with white wool. Leaves lanceolate, with small blunt 

 teeth on the maryin and with 5 parallel lonyitudinal nerves. Heads 

 rather small, in corymbs, on short peduncles. Rays short, yellow. 

 Common in the Sierra Nevada Mountains, north to Oregon, bloom- 

 ing in summer. 



XXXVn. SENE'CIO, Groundsel 



Herbs or shrubs with alternate leaves and heads of yellow 

 flowers either solitary or in corymbs. Bracts of the involucre 

 in a single series, somewhat united, often with a few loose 

 bracts at the base. Akenes slender, with fine and soft copious 

 pappus. 



a. S. vulga'ris L. Old Man of Spring. Annual, from a few 

 inches to a foot high. Leaves rather thick, pinnately cut into 

 toothed lobes. Scales at the base of the involucre tipped with 

 black. Heads sjnall, rayless. This is common in fields and along 

 roads. An introduced weed. 



b. S. Douglas' 11 DC. Perennial, sometimes shrubby, leafy to the top, 

 usually white, with cottony wool more or less persisting. Leaves 

 linear, etitire, acute, or pinnately painted into linear lobes. Heads in 

 corymbs at the ends of the branches, about an inch in diameter. 

 Involucre with a few loose scales at the base. Rays elongated. 

 Widely distributed. 



c. S. aronicoi'des DC. Stems stout, erect, leafy at base, with 

 leaves irregularly and coarsely toothed, 3-6 in. long. Heads rather 

 small, in compound cymes terminating the stems, without rays or 

 with only one or two. Bracts of the involucre without black tips. 

 Common throughout California in low grounds. 



d. S. euryceph'alus Ton. & Gray. Stems stout, erect, leafy, some- 

 what white-woolly when young, becoming smoother with age. Leaves 

 unequally pinnately parted, ivith ivedge-shaped, acutely incised lobes. 

 Heads many in an ample corymb, with 10-12 long and showy rays. 



e. S. Caiifornicus DC. Annual, a foot or two high, with smooth, 

 slender stems. Leaves linear to oblong ; those on the stem clasping at base ; 



