272 THE FLOEA OF THE NOETHEEN TEEEITOEY. 



Pappus of the female florets none, of the sterile disk-florets small. 



Anthers and involucre of Pluohea. — 14. Epaltes. 

 Pappus of scabrous denticulate or almost plumose bristles. 

 Ray-florets usuaUy irregular. Anthers taUed. Involucr& 

 dry or leafy. — 11. Pterigeron. 

 Pappus a short, scaly, jagged tube or cup. Anthers tailed. 



Involucre dry. — 13. Coleocoma. 

 Pappus none or of short obtuse scales. 



Anthers obtuse at the base. — Tribe IV. Anthemidece. 

 Anthers with flne tails. — Tribe V. Onaphaliece. 

 Tribe III. Helianthece. — Leaves opposite or rarely alternate. Plower- 

 heads either heterogamous, with the female florets more or less ligulate, the 

 central ones tubular hermaphrodite or male, or rarely discoid, with all the 

 florets hermaphrodite and tubular. Receptacles with chafiy scales between 

 the florets. Anthers without taUs. Style of SenecionidcB or approaching that 

 of Asteroidece. Pappus of stiff awns, or of short scale's or none. 



Involucre of 2 or 3 rows of bracts, nearly equal or the outer row broader 

 and leafy. 



Pappus none or of very short awns or fine bristles. 

 Receptacle flat or sKghtly convex. 



Style-branches obtuse and flattened. Ray-achenes tri- 

 angular, disk-achenes flat. — ^25. Eclipta. 

 Style-branches almost acute. Ray- and disk-achenes 



usuaUy flattened or thick. — 2Q. Wedeha. 

 Style of the disk -florets undivided. Ray-achenes flattened ; 

 disk-achenes abortive. — 24. Moonia. 

 Receptacle conical. Style-branches truncate. 



Ray-achenes triangular; disk-achenes flattened. — 27. 

 Spilanthes. 

 Pappus of 2 to 4 rigid awns. 



Ray-florets when present, neuter. — 29. Bidens. 

 Ray-florets when present, female. — ^28. Glossogyne. 

 Flower-heads smaU, narrow, collected in dense clusters or compound 

 heads. No pappus. — 30. Plaveria. 



Tribe IV. Anthemidece. — Leaves alternate. Flower-heads heterogamous, 

 the females ligulate or flliform or without corollas, the disk-florets hermaphro- 

 dite or male, or very rarely aU the florets tubular and hermaphrodite. Recep- 

 tacle without or rarely with scales. Anthers without tails. Style of Senecion- 

 idcB. — Pappus none or reduced to a raised border or rarely of short scales. 

 — 31. Centipeda. 



Tribe V. Gna'phaliem. — Leaves alternate, quite entire-. Flower-heads 

 discoid, with all the florets tubular and hermaphrodite or the central ones 

 male, or the florets of the circumference female and filiform or very rarely 

 ligulate or irregular, or rarely the heads more or less dioecious. Anthers with 

 very fine hair-like taUs at the base, sometimes very short (or rarely quite want- 

 ing ?). Style-branches usuaUy nearly terete, very obtuse or truncate. In- 

 volucral bracts most frequently scarious. 



Sub-tribe I. Angianthece. — Flower-heads small, usually numerous, sessfle 

 or nearly so on a common receptacle, in a dense cluster or compound head, 

 usually surrounded by scarious or leafy bracts, forming a general involucre. 

 Florets all hermaphrodite, a few rarely sterile. — ^22. Calocephalus. 



Sub-tribe II. Helichrysece. — Flower-heads distinct, pedunculate or sessile. 

 Female filiform florets few or none, rarely forming 1 or 2 complete outer series. 



