176 KEY AND FLORA 



terminating almost leafless stems, containing many flowers. 

 Involucre of many loose leaf-like scales in several ranks. 

 Ray and disk flowers fertile, yellow. Pappus none. Akene 

 of the ray flowers flattened parallel with the scales; those of the 

 disk with Jf. angles. 



a. B. sagitta'ta Nutt. Densely covered with white wool. Leaves 

 entire, heart-shaped or arrow-shaped, 4-8 in. long, on long petioles. 

 Scapes a foot or two high. Rays yellow, 1-2 in. long. In the 

 Sierra Nevada Mountains to British Columbia, blooming in early 

 spring. 



b. B. deltoi'dea Nutt. Green and almost smooth. Leaves broadly 

 heart-shaped to V-shaped, irregularly serrate or entire, 4-10 in. long. 

 Scapes with small lanceolate or cordate leaves bearing 1-3 heads. 

 Rays an inch or more long. Southern California to British Colum- 

 bia, blooming in early spring. 



XVHI. HELIAN'THUS, Sunflower 



Annual or perennial herbs with the lowest leaves opposite, 

 the upper alternate, all simple. Heads large, with conspicu- 

 ous yellow rays. Bracts of the involucre in several series, 

 green, but not leaf-like. Receptacle flat, with the chaffy 

 scales numerous. Akenes slightly flattened, 4-sided. Pap- 

 pus of 2 marginal scales that fall soon, and more persistent 

 minute bristles between. 



H. Califor'nicus DC. Stems tall, 2-5 ft. high, branching above. 

 Leaves long, lanceolate, or broader at base. Bracts of the involucre 

 narrow, linear-lanceolate, tapering to a long-spreading point. Recep- 

 tacle convex, with the chaffy scales blunt. Akenes flat, with a 

 smooth pappus of 2 or 3 chaffy scales. This grows along streams. 

 The flowers are quite numerous on the branches at the top of the 

 stem. Common from around San Francisco southward. Summer 

 and fall. 



XIX. ENCE'LIA 



Perennial, shrubby at base, branching. Leaves opposite or 

 alternate, generally simple. Heads containing many flowers ; 

 disk flowers perfect ; ray flowers generally present and 

 neutral. Involucre bell-shaped with the scales in several 

 rows one above the other. Akenes flat, with a thin edge but 



