486 



COMPOSITE. 



Tribe 5. Heleniese. Sneezeweed Tribe. 



Herbs or some Eriophyllums suffruticose. Leaves alternate or 

 opposite. Flowers in all our species yellow. Rays present in all our 

 species except Chaenactis. Anthers not caudate. Receptacle naked. 

 Bracts of the involucre in 1 or 2, sometimes in 3 or 4(?) series. Pappus 

 of paleae, awns or bristles, or often wanting. 



A. Leaves opposite; herbage glabrous, pubescent or slightly tomentose, 



never white-woolly. 



Bracts of the involucre imbricated, in more than 1 series; pappus none; 



succulent perennial 36. Jatjmea, p. 518. 



Bracts of the involucre in a single series and 

 United into a toothed cup; pappus paleaceous or none; annuals 



37. Lasthenia, p. 519. 

 Distinct; pappus of paleee or bristles, or both, or none; annuals except one. 



38. BjERIa, p. 519. 



B. Leaves alternate; herbage glabrous or in several genera white-woolly. 



Ray-corollas with a toothed appendage at base opposite the ligule ; pappus 



none; leaves entire or denticulate; annuals. .39. Monolopia, p. 522. 

 Ray-corollas without appendage at base. 

 Pappus present. 

 Bracts of the involucre erect. 

 Rays conspicuous; paleae firm, blunt; leaves divided or incised; peren- 

 nial herbs or suffruticose plants 40. Eriophyllum, p. 522. 



Rays very inconspicuous; palese subulate; leaves narrowly linear and 



entire ; slender annual 41. Rigiopapptjs, p. 524. 



Rays none or the marginal corollas palmately enlarged; leaves 



divided; annuals 42. Chaenactis, p. 524. 



Bracts of the involucre reflexed; rays usually drooping; paleaj short- 

 pointed; leaves often decurrent; perennial herbs 



43. Helexium, p. 525. 

 Pappus none; leaves pinnately parted; low annual 



44. BLENNOSPERMA, p. 526. 



Tribe 6. Madiese. Tarweed Tribe. 



Ours annuals (except one species of no. 45 and no. 54). Herbage 

 glandular, viscid or heavy-scented (except nos. 53, 54, and 55). 

 Leaves alternate or opposite. Bracts of the involucre in a single 

 series, each partly or completely enclosing an achene. Bracts of the 

 receptacle commonly in a single series between disk- and ray-flowers 

 and often united into a cup, or sometimes scattered among the disk- 

 flowers. Rays always present, showy or inconspicuous. Anthers not 

 caudate. Ray-achenes always fertile, without pappus (except nos. 51 

 and 54); disk-achenes fertile or sterile, their pappus paleaceous, awn- 

 like or none. 



A. Ray-achenes laterally compressed, completely enfolded by the deeply 

 sulcate bracts of the involucre which are strongly carinate on the back. 



Rays showy or inconspicuous; disk-flowers few to many; mostly tall plants. 



45. Madia, p. 527. 



Rays inconspicuous; disk-flowers one; low slender plants 



46. Harp^carpus, p. 528. 



