144 University of California Publications in Botany. [ VOL - 3 



broadly ovate, membranous, striate with dark lines: rays about 

 8, golden yellow, 2 or 3 cm. long by about 1 cm. broad, entire 

 or minutely toothed at apex : mature achenes black, flat, 1-nerved 

 on each side, retrorsely barbed on the margins : pappus of 2 

 retrorsely barbed awEs, 3 mm. long, and often a third awn half 

 as long. 



A handsome aquatic, blossoming in the summer and autumn, 

 fairly common in shallow streams from San Bernardino to Los 

 Angeles and perhaps further north : near San Bernardino, Parish. 

 no. 4598; near Riverside, Koethen; Pomona, Baiter, no. 3727; 

 Los Angeles River and Oak Knoll, Braunton, nos. 576, 665, 728 ; 

 Ballona Marshes, Chandler, no. 2029. 



2. B. pilosa L., Sp. PL 832 (1753). 



Annual, 5 to 10 or 15 dm. high, usually branched from the 

 base: herbage from pilose-pubescent to nearly glabrous: leaves 

 pinnate ; leaflets 3 to 5, ovate, serrate, 1.2 to 2.5 cm. long : heads 

 about 1 cm. broad, scattered, the peduncles commonly 2 to 6 cm. 

 long: rays usually none, small and yellowish-white when present: 

 achenes linear, tetragonal, about 1 cm. long, marked with scat- 

 tered ascending barbs : pappus of 2 to 4 retrorsely barbed awns. 



A native of -the tropics ; frequent in Southern California as a 

 weed. 



52. MELAMPODIUM L. 



Herbaceous plants with ample opposite leaves. Heads 

 medium-sized, in leafy-bracted cymes or panicles. Outer in- 

 volucre of several loose often foliaceous bracts; inner involucre 

 of smaller bracts each completely enclosing a marginal achene 

 with which it is deciduous as a pericarp-like accessory covering. 

 Rays yellow or white. Disk yellow, of hermaphrodite-sterile 

 flowers. Pappus none. 



1. M. perfoliatum (Cav.) HBK., Nov. Gen. & Spec. iv. 274 

 (1820). Alcinia perfoliata Cav., Ic. i. 10, t. 15 (1791). 



A coarse widely branched annual, commonly 10 or 12 dm. 

 high: leaves 2 dm. or less long, scabrous, broadly ovate, acute, 

 contracted below as if into a winged petiole, connate around the 

 stem in pairs, the margins dentate : heads on slender peduncles : 

 bracts of the outer involucre 1 to 1.5 cm. long, united at base. 



