COMPOSITE FAMILY. 181 



-I- •*- Pappus none nt all to the outer pistillate and fertile flowers, but of some slender 

 bristles in the central and perfect yet seldom fruit-bearing flowers : scales of 

 the involucre woolly. 



13. FILAGO. Heads small crowded in close clusters, of many inconspicuous 



flowers, each fertile pistillate flower in the axil of a thin and dry chaffy scale, 

 and with a very slender thread-like corolla; the central flowers with a more 

 expanded 4 - 5-toothed corolla. Low herbs, clothed with cottony wool : leaves 

 entire, 

 -t- H- ■<- Pappus of all the flowers composed of bristles : no chaff among the flowers. 



14. ERECHTHITES. Heads of many whitish flowers, with a cylindrical involucre 



of many narrow and naked scales in a single row: outer flowers with very 

 slender corolla: inner with more open tubular corolla. Akenes narrow: 

 pappus of copious very fine and soft naked white hairs. Rank coarse herb. 

 37. ERIGERON. One species has such short and inconspicuous rays that it may be 

 looked for here. 



15. GNAPHALIUM. Heads of very many whitish or yellowish flowers, surrounded 



by an involucre of many ranks of dry and white or otherwise colored (not 

 green) scarious and persistent scales woolly at base; the flowers all fertile, 

 the outer ones with pistil and very slender corolla, the central ones perfect 

 and with more expanded 5-toothed corolla. Pappus a row of very slendeT 

 and rough ish bristles. Cottony herbs. 



16. ANTENNARIA. Like Gnaphalium, but the plants nearly or quite dioecious: 



the staminate flowers with a simple style, but the ovary sterile, and their 

 pappus of stouter bristles which are thickened at the summit and tliere more 

 or less barbed or plumed. 



* * Only one kind of flowers in the head. 



■*- Scales of the involucre dry and papery or scarious, often colored (i. e. not green), 



nut withering. (Everlastings.) 



•i-t- Many flowers in the head: scales of the involucre in many ranks. 



16. ANTENNARIA. Flowers dioecious, in one plant all pistillate, with very slender 

 . corollas and a pappus of long and very fine hair-like naked bristles; in the other 



staminate (with a simple imperfect style), and the pappus of thicker bristles 

 enlarging and somewhat plumed or barbed at their summit. Leaves and 

 stems cottony. 



17. RHODANTHE. Flowers perfect, with open 5-toothed yellowish corollas. In- 



volucre (silvery or rose-colored), smooth, obovate or top-shaped. Akenes 

 woolly: pappus of numerous plumose bristles. Leaves and stems smooth 

 and naked. 



18. AMMOBIUM. Flowers perfect, with yellow 5-lobed corollas, surrounded by a 



silvery-white involucre. Chaffy scales on the receptacle among the flowers. 

 Akenes flattish-4-sided : pappus of 4 teeth, two of them prolonged into a 

 bristle. Leaves and stems white-cottony, the latter with leaf-like wings. 



*+ 4-f Only 3 or 4 flowers in each head. 



19. HUMEA. Flowers perfect, purplish, surrounded by a few dry and scarious 



scales of the involucre: no chaff on the small receptacle. Akenes smooth: 

 no pappus. Herbage green, not cottony: the small heads drooping in an 

 ample compound panicle. 



+— t- Scales of the involucre not dry and scarious or papery : flowers all perfect. 



++ Flowers yellow, with chaff between them : akenes flat, bearing 2-4 awns or bristles. 



53. BIDENS, and 52. COREOPSIS: a few species have no ray-flowers. 



++ ++ Flowers yellow : no chaff: akenes not flat : pappus of copious very soft andflne 

 down-like bristles. 



30. SENECIO, one or two species which are destitute of ray-flowers. 



*+++++ Flowers not yellow nor orange : no chaff among them. 



a« Branches of the style slender and rough all over loith minute bristles. 



20. VERNONIA. Heads corymbed, with an involucre of many imbricated scales, 



and 15 to 30 or more rose-purple flowers. Lobes of the corolla slender. Akenes 

 cylindrical, several-ribbed: pappus of copious hair-like bristles, surrounded 

 at base by an outer set of very short and fine scales or scale-like bristles. 

 Leaves alternate. 



