356 ASTERACEAE. 



1. L. debilis serrata Gray. Stems simple or rarely branched 

 above, 2-6 dm. high, very leafy, glabrous except the inflorescence, 

 this puberulent; cauline leaves lanceolate-linear or lanceolate, the 

 lower broader, spatulate to obovate, all sharply serrate, the upper- 

 most passing into slender bracts; racemes few-many-flowered; 

 pedicels slender; calyx-lobes narrowly-subulate, twice the length 

 of the tube, and nearly equaling the corolla; corolla-tube slender, 

 2 cm. long, in age splitting up from the base as in Lobelia, pale 

 blue; the larger lobes deep violet, 6-8 mm. long. 



Frequent in moist places in the canyons of the San Gabriel and 

 Santa Ana Mountains. 



Family 104. ASTERACEAE. Aster Family. 



Annual or perennial herbs or shrubs with alternate or 

 opposite leaves. Flowers in heads, borne on the en- 

 larged summit of the peduncle (receptacle) and sur- 

 rounded by the bracts of the involucre. Receptacle 

 naked or with bracts subtending the flowers or with 

 bristles among the flowers. Calyx-tube united with the 

 ovary, the limb when present called pappus, and con- 

 sisting of awns, hairs, bristles, scales or paleae. Corolla 

 tubular and 5-toothed or 5-lobed, or the limb strap- 

 shaped (ligulate) and toothed or entire at the apex, those 

 of a head all tubular, all ligulate or of both kinds. When 

 both kinds are present the marginal ones are ligulate 

 and are called ray-flowers, the inner are tubular and are 

 called disk-flowers. Stamens 5; filaments free; anthers 

 united and forming a tube, or nearly or quite free in 

 AmbrosicB and the filaments more or less cohering. 

 Styles 2-lobed, the lobes, stigmatic on the inner surface. 

 Ovary 1 -celled, becoming an achene in fruit. Pappus 

 commonly persistent. 



Key to the Tribes. 



Heads all alike. 



Heads composed of both ray- and disk- 

 flowers or of disk-flowers only. 

 Anthers not caudate at base. 

 Receptacle naked. 



Bracts of the involucre well-im- 

 bricated. 



