COMPOSITE . 333 



of 20 long-plumose bristles. On high stony hills, near Stein mountain 

 southeastern Oreg> n. 



Tribe iv Helianthoidese B. & H. Gen. ii, 166. Heads heterog- 

 amous and the pistillate flowers ligulate and radiate, or rarely with 

 corolla wanting, and then sometimes monoecious: or sometimes homo- 

 gamous by the absence of the ray-flowers: disk-flowers all with regular 

 4-5-toothed tubular corolla. Receptacle usually with palest or chaff 

 subtending either all the flowers or the marginal ones only. Anthers 

 at most sagittate^ not caudate at base. Style-branches of the herma- 

 phrodite or sterile flowers truncate or continued into a hairy conical 

 to subulate appendage. Pappus various or none: never of truly cap- 

 illary bristles. 



SUBTRIBE i IVE^E. Heads androgynous, having few fertile 

 flowers at the margin. 



35 Iva Fertile flowers 1-5, with or without the tahe or cup representing 

 a corolla 



SUBTRIBE n, AMBROSIEJE. Heads homogamous, monoecious : 

 the fertile ones with 1-4 apetalous flowers in a closed bur-like or 

 acheiie-like pointed involucre ; the sterile with .numerous flowers 

 in an open involucre. 



* Involucre to the staminate flowers 5-12 lobed or almost truncate 



36 Ambrosia Fertile involucres 1-flowercd, achene-like, bearing no more 

 than one row of tubercles or short spines. 



37 Gsertneria Fertile involucres 1-4-flowered, 1-4-celled, armed with 

 more than one row of tubercles or prickles. 



* * Involucre of the staminate heads of a few distinct scales 



38 Xanthiuin Fertile involucres bur-like, 2-celled, 2-flowered, beset with 



with numerous hooked prickles. 



SUBTRIBE in VERBESINE^ Heads radiate with either neutral 

 or pistillate ray flowers or rayless : the disk-flowers perfect and 

 fertile. Receptacle chaffy. Achenes thick and 3-4-angled or 

 those of the disk laterally compressed. 



* Receptacle elongated, becoming columnar. 



39 Rudbeckia Rays neutral or rarely wanting : achenes quadrangular 

 and compressed. 



* * Receptacle flat , concave or rarely conical; 



*- Rays pistillate and fertile. 



40 Balsamprhiza Pappus none : achenes of the ray obcompressed ; of the 



disk prismatic-quadrangular or somewhat compressed. 



41 Wyethia Pappus a chaffy-coriaceous crown or cup, continuous with 

 the broad summit of the achene . 



*- *- Rays neutral, rarely wanting. 



42 Helianthella Achenes flat, the thin edges more or less wing-like : 

 pappus a pair of persistent awns or cbaffy teeth and a crown of inter- 

 mediate chaffy scales. 



