254 XXXIX. COMPOSITAE. 



Tribe IV. HELIANTHOIDEAE.— Heads heterogamous, radiate or rarely discoid; outer florets 

 female or neuter, ligulafce, rarely irregular or 0, or all the florets tubular, her- 

 maphrodite or male ; rarely the heads unisexual and anthers free. Eeceptaole 

 with chafiy or rigid scales amongst the florets. Anthers usually obtuse at the 

 base. Style-arms of the hermaphrodite florets truncate. Pappus of short scales 

 or awns or 0. Herbs, with opposite or rarely alternate leaves. 



* Xanthium. Heads unisexual. Female florets 2 together, forming with the invo- 



lucres a 2-4-oelled prickly burr. Male florets in globose heads. Herbs, with 

 alternate leaves. Pappus 0. 

 13. SiBGESBECKiA. Involuoral bracts in 2 series, the outer leafy and glandular, the 

 inner and the reoeptaoular scales enclosing the florets. Pappus 0. 



16. BiDBNS. Involuoral bracts in 2-3 series. Eay-florets, when present, neuter. 



Pappus of 2-4 rigid awns. 



* Madia. Involucre angular. Eay-florets 1-2-seriate, fertile ligule short or 0. Disk- 



florets hermaphrodite, fertile or sterile. Achenes compressed, enclosed in the 

 infolded involuoral bracts. 



V. ANTHEMIDBAB. — Heads heterogamous, radiate or discoid ; the females ligulate or 

 filiform or without corollas ; the disk-florets hermaphrodite or male ; or rarely 

 all the florets tubular and homogamous. Anthers usually obtuse at the base. 

 Style-arms usually truncate. Pajipus or represented by a raised border or by 

 minute scales. Leaves alternate. 



Beceptacle with chaffy scales. Heads radiate. 



* Achillea. Heads small, numerous. Eays short and broad. Achenes compressed, 



winged. 



* Anthemis. Eays elongated. Achenes terete, ribbed or angled. 



Beceptacle naked. Bays white or yellow. 



* Mateicaeia. Eeceptacle conical, often elongating. Eays female or 0. 



* Gheysanthemum. Eeceptacle convex, flat. Rays female. 



Heads discoid, or apparently discoid. 



17. CoTULA. Heads pedunculate. Achenes compressed or turgid, acute or truncate. 



18. Centipeda. Heads axillary, sessile. Corollas of female florets minute, 4-toothed. 



Achenes trigonous or tetragonous. 



* SoLivA. Heads sessile. Achenes compressed, crowned by the indurated style. 



Pappus 0. 



19. Aebotanella. Leaves densely crowded, rarely spreading. Style-arms short, trun- 



cate. Female florets slender. 



Florets all tubular. 



* Tanacetom. Heads corymbose. Eeceptacle broad. Aohene crowned with an 



epigynous disk. 



* Aetbuisia. Heads in elongated panicles. Eeceptacle narrow. Pappus 0. 



VI. SEHBCIONIDBAE. — Heads heterogamous with the ray-florets ligulate or flliform, or 

 homogamous with all the florets hermaphrodite and tubular. Eeceptacle usually 

 naked. Involuoral bracts herbaceous, usually in a single row, with or without 

 a, few bractlets at the base. Anthers usually obtuse at the base. Style-arms 

 usually penicillate at the base, rarely produced into appendages. Achenes 

 usually crowned with a setose pappus. 



20. Bebchthites. Herbs, with the outer female florets usually in 2-3 series, very 



slender, flliform. 



21. Bbaohyglottis. Shrubs, Outer florets small, 2- lipped. Achene terete, papillose. 



22. Senecio. Herbs or shrubs, with terminal inflorescence. Outer florets ligulate or 



tubular. 



VII. GALENDULACBAB.— Heads heterogamous, radiate. Involuoral bracts 1-2-seriate, or 

 rarely 3-4-seriate, herbaceous, Rays in 8 series, female or rarely neuter, 8-d'en- 

 tate. Disk-florets hermaphrodite, rarely fertile, tubular. Style-arms com- 

 planate, truncate, concrete or thickened at the base. Herbs or shrubs, with 

 alternate or rarely opposite leaves. 



