COMPOSURE. 



Tribe 6. HELENIEAE. 



iy with 



72. Psilostrophe. 



A. Ray-flowers persistent on the achenes, falling away with them, papery. 



" iic 



B. Ray-flowers deciduous, or wanting. 



* Plants not dotted with oil-glands. 



a. Pappus none. 73. Flaveria. 



b. Pappus present (in all our species), of separate scales or bristles. 



i. Bracts of the involucre petal-like, colored, their margins and apices scarious. 



Leaves, at least the lower, pinnately parted, or pinnatifid; rays none; corolla-lobes of 



disk-flowers ovate. 74. Hymenopappus. 



Leaves entire; rays present, or none; corolla-lobes of disk-flowers linear. 



75. Polypteris. 

 2. Bracts of the involucre herbaceous, not scarious-tipped, nor petal-like, appressed, or 



spreading. 

 Receptacle naked. 



Bracts of the involucre appressed. 



Achenes 4-angled, linear or oblong. 76. Picradeniopsis. 



Achenes 5-io-ribbed or 5-io-angled, top-shaped. 



Outer involucral bracts separate. 77. Tetraneuris. 



Outer involucral bracts connate at base. 78. Picradenia. 



Bracts of the involucre spreading, or reflexed at maturity. 79. Helenium. 

 Receptacle with bristle-like chaff. 80. Galliardia. 



* * Plants dotted with oil-glands, especially the leaves and involucre. 

 Involucral bracts more or less united; style-branches of the disk-flowers elongated. 

 Involucral bracts united at the base. 81. Boebera. 



Involucral bracts united high up into a cup. 82. Thymophylla. 



Involucral bracts separate; style-branches of the disk-flowers very short. 



83. Pectis. 



Tribe 7. ANTHEMIDEAE. 



* Receptacle chaffy. 

 Achenes flattened ; involucre obovoid to campanulate ; heads small. 



84. Achillea. 

 Achenes terete; involucre hemispheric ; heads large. 85. Anthemis. 



* * Receptacle not chaffy, naked, or sometimes hairy. 

 I. Ray-flowers usually present, sometimes wanting; rays large. 

 Receptacle flat to hemispheric ; bracts of the involucre in several series. 



86. Chrysanthemum. 

 Receptacle conic to ovoid; bracts in few series; rays white or none. 



87. Matricaria. 

 2. Ray-flowers none ; heads small. 



Heads corymbed; pappus a short crown; flowers yellow. 88. Tanacctum. 



Heads racemose, spicate or panicled; pappus none. 89. Artemisia. 



Tribe 8. SENECIONEAE. 



Leaves all basal; heads on scapes. 

 Head solitary; flowers yellow. 

 Heads corymbed ; flowers white or purple. 



^ V ::^^ raysyellow - . 



Flowers white, whitish or pinkish- rays none 



disk - flow *rs perfect. 93 . Erechtites. 



Involucre of about 5 bracts; sap milky. ^ Mesadenia. 



Involucre of about 12 bracts and several smaller outer ones. 



Flowers yellow; ray-flowers mostly present. c Senecb*' 



Tribe 9. CYNAREAE. 



* Achenes inserted on the receptacle by their bases, not oblique. 

 Receptacle densely bristly. 

 Filaments separate. 



Involucral bracts hooked at the tip ; leaves not bristly. 97. Arctium 

 Involucral bracts not hooked; leaves bristly. 98. Carduus. 



