270 COMPOSITE. Melampodine^. 



SubtribeG. Anthemideje. Heads mostly heterogamous. Pappus none or coroni- 

 form, rarely squamcllate. Anthers not caudate. Branches of the style tmncate 

 and bearded at the apex, rarely terminated by a short cone. Leaves mostly 

 alternate. 



Subtribe 7. Gnaphalie^. Heads homogamous and discoid, or rarely heteroga- 

 mous. Anthers caudate. Pappus of capillary or setaceous bristles, very 

 rarely none. Leaves mostly alternate. 



Subtribe 8. Senecione^. Heads homogamous or heterogamous, discoid, or ra- 

 diate. Anthers not caudate. Pappus of capillary bristles, or very rarely 

 wanting in the exterior flowers. Leaves alternate. 



Subtribe 1. Melampodine^, DC. (Polygamia Necessaria, Linn.)— 

 Flowers all unisexual; the pistillate and staminate flowers either in different 

 individuals, or in different heads of the satne plant, or in the same head. 

 Anthers not caudate at the base. Receptacle almost always chafly. Pap- 

 pus none, or somewhat coroniform, or awned, never of bristles. 



CONSPECTUS OF THE GENERA. 



Div. 1. Melampodie;e. — Heads moncecious, radiate. Achenia corticate. 

 G9. Melampodium. Inner scales of the involucre investing the achenia. 



Div. 2. MiLLERiE^E.— Heads moncecious, radiate. Achenia not corticate nor winged. 

 70. Blennosperma. Receptacle naked. Achenia pulverulent-papillose. 

 7L PoLYMNiA. Receptacle chaffy. Achenia ob ovoid : pappus none. 

 72. Chrysogonum. Receptacle chaffy. Achenia obcompressed 4-angular: pap- 

 pus coroniform-toothed. 



Z>iv. 3. SiLPHiEJE. — Heads monoecious, radiate; the rays deciduous. Achenia not 

 corticate, obcompressed, or winged. Pappus of two teeth or short awns. 



73.' SiLPHiUM. Achenia winged, in more than one series. 



74. Berlandiera. Achenia wingless, one adhering to each inner involucral scale. 



75. Engelmannia. Achenia wingless, free : pappus 2-auriculate-squamellate. 



Div. 4. PARTiiENiEiE. — Hcads moncecious, radiate : rays raarcescent. Achenia not 

 corticate, obcompressed. 



76. Parthenium. Achenia 5 ; their callous margins united at the base with the 



chaff of 2 contiguous sterile flowers. 



Div. 5. lvE.iE. — Heads monoecious, not radiate. Anthers scarcely united. 



77. Cyclach;ena. Heads glomerate-paniculate, bracteate: the central flowers 



abortive. 



78. IvA. Heads bracteate. Receptacle chaffy. Flowers glabrous. 



79. PiCROTHAMNUS. Receptaclc naked. Achenia and corolla woolly. 



Div. G. Ambrosieje. — Heads heterocephalous ; the sterile and fertile heads in the 

 same or different plants, not radiate. Anthers distinct. 



80. Ambrosia. Fertile involucre 1-cellcd, 1-flowered, not spinose throughout. 



81. Franseria. Fertile involucre 1-4-celled, sjiinose ; the sterile 8-12-toothed. 



82. Xanthium. Fertile involucre 2-celled; the scales of the sterile distinct. 



