COMPOSITyr,. (COMPOSITK FAMILY.) 219 



Snbtribc 3. Bncchnricletv &. Tart-honaiithfoe. Flowors of the head all tuba- 

 Ijir, eitlier dineoious or iiioiia'ciou-', n.-iim-ly, the Ktiiniinitto and pistillate (lowtTH eitlier in 

 different la-ads on distinct plants, or in the sanii- liead. Corolla of the pistillate fertile flow- 

 ers a very slender tube fiheathing the style, and truncat4! at the summit. 



23. Pliichrn. Heads contJiining a few perfect but sterile flowers in the centre, and many 



pistillate fertile ones around them. Anthers tiileJ at the base. I'uppus capillary. 



24. BacchnrU. Heads dicGcious, some all pistillate, others all stamiaate, on different plants. 



Anthers tailles-s. Pappus capillary. 



Tribe IV. SENECIOXIDE.^. Heads various. Branches of the style in the fertile 

 flowers linear, thiokish or convex externally, flat intemalh, hairy or pi^ncil-tufted at the 

 apex (where the stiginatic lines terminate abruptly), and eitlier truncate, or continued be- 

 yond into a bristly-hairy appendage. — Leaves either opposite or alternate. 



Subtribe 1. Melnmpodiiierc. Flowers none of them truly perfect, but either stam- 

 inate or pistillate ; the two sorts either in the same or in different heads. Anthers tailless. 

 I'uppus, if any, never of bristles. 



• Heads containing two kinds of flowers, the marginal ones pistillate, the central and tubular 



Rtaminate flowers having a style, but alwais sterile. 

 <- Fertile flowers with a li^ulate corolla (rarely wanting in No. 25) receptacle chaffy. 



25. Polyimiln. Achenia thick and turgid, roundi.sh. Pappus none. 



26. Chrysnjfonum. Achenia flattish. I'appus a one-sided 2 - S-toothed chaffy crown. 



27. Sil|ihluin. Achenia flat, wing-margined, numerous in several rows : rays deciduous. 



28. Pat-theiiiuin. Achenia fl.at, slightly margined: rays very short, persistent. 



<- t- Fertile flowers with tubular or no corolla : no pappus. 



29. Ivn< Achenia short and thick : recept;icle with narrow <'haff. 



57. Arlemlsln, in part. Achenia short and small : receptHcle naked. 



11. Adeiiocauloii. Achenia elongated, bearing stalked glands : receptacle naked. 



• * Heads of two sorts, one containing staminate, the other pistillate flowers, both borne on 



the same plant ; the pistillate only 1 or 2. in a closed involucre re.-sembling an achenium or 

 a bur ; the st.iuiinate several, in an open cup-shaped involucre. 



30. Ambrosia. Fertile involucre (fruit; .small, l-flowered, pointed and often tubercled. 



31. Xaiithluin. Fertile involucre (fruit) an oblong prickly bur, 2-celled, 2-flowered. 



Sul>tribe '4. Ilrlinitlhrie. Hcadsradiate.orr.irely discoid; the rays ligulatc. the disk- 

 flowers all perfect and fertile. Uecept.icle chaffy. Anthers bl.ickish, taillejss. Pappus none, 

 or a crown or cup, or of one or two chaffy awns, never capillary, nor of several uniform 

 chaffy scales. — Leaves more commonly opposite. 



* Kays pistillate and fertile : achenia 3 -4-sided, slightly if at all flattened. 

 1- Involucre double ; the outer forming a cup. 



32. Tetragonotheca. Outer involucre 4-leaved. Achenia obovoid. Pappus none. 



<- ^- InV' 'lucre of one or more rows of separate scales. 

 3.3. Ec-lipta. Receptacle flat ; its chaff bristle-shaped. #appus obsolete or none. 

 3t. Ilorrlvhia. Ueccpt.acle flat, its chaff .-icale-like and rigid. Pappus an obscure croTrn. 

 35. HeliopMis. Receptacle conical ; ita chaff linear. Pappus none or a mere border. 



• • Kays sterile (either entirely neutral or with an imperfect style), or occa.'sionally none ; ache- 



nia 4-angular or flatteneil laterally, i.e. their edges directed iuwards and outwards, th^ 

 ch;iff of the receptacle embracing their outer edge. 



<- Receptacle elevaU^d, conical or columnar. Pappus none or a short crown. 

 3f). Echiiinrrn. Kays (very long) pistillate, but sterile. Achenia short, 4-sided. 

 37 Riiilberkin. Kays neutn\l. Achenia 4sicliMl, flat at the top, inarginless. 

 3.S. Ltiint liys. Itays few, neutral. Achenia flattened laterally and margined. 

 «- <- Receptacle flattish or conical. Pappus chaffy or awned. 



39. HclianthuH. Achenia flatteneil, margiulcss. Pappus of 2 very deciduous chaffy scales. 



40. Actliionierlii. Achenia very flat, wing-margined, bearing 2 persistent awns. 



