482 



COMPOSITE. 



May. This is. doubtless, a reduced form of B. bicornuta (Gray) 

 while the next is a still further reduction. 



6. B. humilis Greene. Very dwarf, 1 in. high; calyx-segments 

 unequal; corolla minute, white, 1 line long, obscurely bilabiate, the 

 ovate-oblong acute segments not very unlike. 



Sonoma Co. 



2. HOWELL I A Gray. 



Either aquatic or of muddy margins of pools. Flowers more or 

 less cleistogamous. Calyx-tube united for its whole length to the 

 ovary, the limb with slender segments. Corolla not surpassing the 

 calyx, its very short tube divided nearly to the base on the 

 (apparently) upper side; lobes oblong, nearly equal, three united 

 higher. Ovary 1-celled, the filiform parietal placenta? each with 3 to 

 5 ovules. Capsule membranaceous, bursting irregularly on one side. 

 (In honor of Thos. Howell of Portland, now author of a pioneer 

 flora of Oregon, Washington and Idaho.) 



1. H. limosa Greene. Weak and procumbent, the branches 1 ft. 

 long, sometimes matted; leaves lanceolate, sessile, entire, 1 in. long; 

 flowers cleistogamous; capsule clavate-oblong, £ in. long, crowned by 

 the 5 triangular calyx-teeth. 



Muddy shores: Suisun. May. This may be simply a terrestrial 

 form of H. aquatilis Gray. 



101. COMPOSIT/C. Sunflower Family. 



Annual or perennial herbs or shrubs with alternate or opposite 

 leaves. Flowers in heads, borne on the enlarged summit of the 

 peduncle (receptacle) and surrounded by the bracts of the involucre. 

 Receptacle with bracts subtending the flowers, or with bristles among 

 the flowers, or without bracts or bristles (naked). Corollas tubular 

 and 5-toothed or -lobed, or the limb strap-shaped (or ligulate) and 

 toothed at apex, those of a head all tubular or all ligulate or of 

 both kinds. When both kinds are present the flowers with the 

 ligulate corollas occupy the margin of the head and are called ray- 

 flowers, and the ligulate corollas, rays; the flowers with the tubular 

 corollas occupy the center and are called disk-flowers. Ray-flowers 

 commonly pistillate, sometimes perfect or neutral; disk-flowers com- 

 monly perfect, often staminate or pistillate. Heads with both ray- and 

 disk-flowers are called radiate; with disk-flowers only , discoid. Calyx- 

 tube united with the ovary, the limb when present called a pappus 

 and greatly varied in structure, consisting of awns, hairs, bristles, 

 scales or palea?, or in many cases appearing as a mere crown or ring or 

 wholly obsolete. Stamens 5; filaments free; anthers united and 

 forming a tube, or nearly or quite free in Ambrosiea*. Style divided 

 above into 2 long branches which bear stigmatic lines on the inside. 

 Ovary 1-celled, 1-ovuled, maturing into an achene, crowned by the 

 pappus when that is present. Pappus commonly persistent and 

 assisting in the dispersion of the 1-seeded fruit. 



