296 COMPOSITiE. Xa.nthium. 



86. Balsamorhiza. Rays numerous. Pappus none. Receptacle flat. 



87. Hemopsis. Rays 10-15. Pappus none. Receptacle conical. 



88. Tetragonotheca. Rays G-9. Pappus none. Scales of the exterior invo- 



lucre 4, foliaceous, united towards the base. 



89. Halea. Rays 6-12. Pappus of numerous distinct, small and rigid scales. 



Exterior involucre of 4-5 foliaceous scales vmited below. 



Dlv. 2. EUHELIANTHE.E. — Rays sterile. Achenia never obcompressed. 

 * Pappus coronifonn, somewhat 2-iootkcd, or noTie. 



^- Receptacle conical or columnar. 



90. Echinacea. Achenia quadrangular. Chaff" with a cartilaginous cusp. 



91. Rudbeckia. Achenia quadrangvilar. Chaff" navicular or concave. 



92. Lepachys. Achenia compressed, somewhat 1-2-winged, 1-2-toothed. Chaff" 



truncate. 



93. Dracopis. Achenia terete. Chaff" linear. 



•)- +- Receptacle flat or convex. 



94. Gymnofsis. Pappus coroniform. Achenia enclosed in the chaff". 



95. Encelia. Pappus none. Margins of the compressed achenia villous. 



* * Pappus aristiform or squamdliform. 



96. Viguiera. Pappus of 4 squamellce and 2 awns. Involucre scarcely im- 



bricated. 



97. Helianthus. Pappus of 2 chaff'y awns and often 2-4 squamellas, caducous. 



Involucre imbricated. Aclienia wingless. 



98. Helianthella. Pappus lacerate-toothed or awned at the angles. Achenia 



slightly winged or margined. 



99. Actinomeris. Pappus of 2 persistent awns. Achenia winged. 



Div.Z. C0REOPSIDE.E. — Rays sterile. Achenia obcompressed, not rostrate. Awns 

 not retrorsely hisjDid. 



100. Agarista. Aclienia villous. Pappus of 2 long cliaff"y scales. 



101. Coreopsis. Achenia mostly glabrous. 



Div. 4. Bidentide^. — Rays sterile. Achenia cither obcompressed or rostrate. 

 Awns retrorsely hispid. 



102. Cosmos. Achenia rostrate. Awns deciduous. Chaff" slender. 



103. CosMiDiuM. Achenia not rostrate. Awns persistent. Chaff" short and ob- 



tuse. Disk-corolla deeply cleft. 



104. BiDENS. Achenia rostrate or erostrate. Awns persistent. Disk-corolla 



5-toothed. 



Div. 5. VEKBEsiNEiE. — Rays fertile, rarely "^none. Achenia mostly compressed or 

 obcomjiressed, with a thin exterior integument. 



* Achenia all obcompressed. Disk-corolla unth a barbelkde ring. Involucre dmible. 



105. Leptosyne. Pappus minute and cup-shaped. Rays 8-15. 



106. Tdgkermannia. Pappus none. Rays 15-20. 



