24 Flora of the Malayan Peninsula. 



(calyculiis) at their bases ; heads homogamous ; anther- 

 cells sub-entire at the base ; receptacle naked {Sene- 

 cionida) : — 

 Leaves alternate ; pappus of fine hairs, style-arms of 

 hermaphrodite flowers truncate or obtuse, penicillate 

 or with a hairy tip : — 



Heads ebracteate ; florets purple . . . . 12. Emilia. 



Heads bracteolate ; florets yellow . . . . 13. Gynuea. 



Keceptacles paleaceous ; anthers sub-entire at the base ; 

 bracts of involucre 1- to many-seriate ; heads usually 

 radiate, heterogamous ; style-arms truncate or appendicu- 

 late, or those of the sterile florets entire ; pappus of 2 to 

 4 arms or paleaceous or absent ; leaves at the base of the 

 stem usually opposite, those higher up opposite or alter- 

 nate (Heliantlioidccc) : — 



Pappus of only 4 bristly awns, or cup-like or absent : — 

 Cypselas all thick, or those of the ray-florets 3-angled 

 and those of the disc laterally compressed ; pappus 

 cup-like or composed of 2 to 3 stiff chaffy or bristly 

 arms, with or without intermediate smaller scales or 

 altogether absent ; leaves usually opposite : — 



Inner bracts of the involucre embracing and en- 

 closing the cypselas of the fertile ray-florets ; 

 pappus absent, outer bracts of involucre 5, glan- 

 dular . . . . . . . . 14. SlEGESBECKIA. 



Inner bracts of the involucre all flat, scales of 

 receptacle flat, very narrow, usually few ; disk- 

 florets 4-5-fid, ligules small ; pappus absent, or 

 if present shortly 2-awned ; outer bracts of invo- 

 lucre numerous . . . . . . 15. Eclipta. 



Scales of the receptacle concave or complicated 

 more or less enclosing and embracing the disk 

 florets : — • 



Cypselas not winged, compressed or 3-5-angled, 

 ray-florets yellow with large ligules ; disk-cyp- 

 selas with 1 or 2 short deciduous awns ; leaves 

 all opposite . . . . . . . . 16. Wedelia. 



Cypselas of the disk-florets ciliate, winged on 

 the margins, laterally compressed ; heads small ; 

 leaves always opposite . . . . . . 17. Spilanthes. 



Cypselas more or less depressed from the top ; pappus 

 of 2 (rarely 3 or 4) bristles or absent : — 



Outer bracts of the involucre almost equal ; herba- 

 ceous ; inner bracts separate, almost resembling 

 the scales of the receptacle ; ray-florets fertile ; 

 leaves opposite : — 



Cypselas flat, their margins lacerate and winged ; 



pappus composed of bristles . . . . 18. Synedrella. 



Outer bracts of the involucre few, small ; inner 

 bracts connate below, membranous : — 

 234 



