THISTLE FAMILY 837 



Receptacle not chafTy; style or style-branches of the hermaphrodite flowers mostly 

 truncate. 

 Plants dioecious, or the pistillate heads with a few hermaphrodite flowers in the 



Pappus-bristles of the pistillate flowers falling off in a ring: central hermaph- 



roditc llowers none. 55. Ante.vn\ri\ 



Papi)us-l)ristles of the pistillate flowers falling off separately; central hermaph- 

 rodite flowers present ui Mie pistillate heads. 56. An\pha.lis 



Plants not dioeciotis; flowers fertile tliroughout the heads, hermaplirodite in the 

 nuddle, surrounded by pistillate ones. 57. Gnaphalium. 



Tribe 5. ADEXOCAULEAE. 

 Leaves cordate, white-woolly beneath. 58. Adexocaulon. 



Tribe 6. HELIANTHEAE. 

 A. Bracts (at least the outer series) not enclosing the achenes of the rays; plants not 

 ^ia.riciiii3rr- viscici . 



I. Disk-flowers hermaphrodite but sterile. 



JNIarginal pistillate flowers, with conspicuous rays. 



Achenes not flattened; ligules in ours white; "involucres of verv dissimUar sets 

 Achenes to ttened; ligules i.a ours vellow. ^^^ ^'^^'-^'^ODimi. 



Ray-flowers in 2-3 series; achenes falling away free. 



■D^ , fl . , . , 60. SlLPHIUM. 



Kay-flowers m 1 series; achenes adnate to 2 or 3 paleae and faUing awav 

 witn tnem. gj Exgelmaxnta 



IVIarginal pistillate floweis reduced to a trtmcate or obUquely-cleft tube; the 

 hgules, if any, reduced to 2 or 3 small teeth. 

 Acauiescent cespitose perennials; pappus of a pair of lanceolate membranous 

 scales. Qo BoLOPHYT v 



II. Disk^fl^wers"femie.^^'' ^""^'^"^ °°"''- ^^' Parthenice. 



^' ^^^oSSY'"'' ft'^tiie: the Ugules vnth very short tube, persistent on the achenes 

 and beconung papery in texture. 

 Achenes of the disk compressed ; leaves entire. 64 Cr \.ssix \ 



Achenes obtusely 4-angled. "-nAssi.MA. 



Leaves toothed; paleae pointless, partly enclosing the achenes. 

 Leaves entire; paleae Unear-lanceolate, not enclosing the'achenes. ' (^ Kalliac- 

 b. Ray-co/;!ia^s^dec1d(?oTi^To"m°tL achenes or wantin^^ ''■ ^-^^-^^^oh^hiza. 

 1. Pappus a crown or none, or of a few squamellae on the angles of the achenes 

 and rarely nunute ones between. 

 a. Ach^es of the disk-flowers not obcompressed (except in Ratibida and 

 Ji.irnenesia)\ paleae ustially more or less concave and clasping 

 Receptacle conic, subulate or columnar. 

 Achenes 4-angled. 



Ray-flowers purplish or rarely whitish: disk-coroUas almost 



without a tube: pappus coroniform. 66. Braun-eri\ 

 Kay-flowers yeflow or none; disk-coroUas with a short but mani- 

 fest tube. 

 Achenes quadrangular-compressed; apex of the achenes 



covered by the base of the corolla-tube. 

 , . , „ 67. Gymnolomia. 



Achenes nearly equally 4-angled; apex not covered by the 

 base of the corolla. 68. Rudbecki\. 



Achenes 5-angled; ray-flowers white. 70. Galinsogv 



Actienes flattened, broad-margined or winged. 



Receptacle from flat to convex. ^^' ^^''^^'lO-^- 



Achenes of the disk neither sharp-angled, margined, nor winged 



Kays fertile, their achenes commonly 3-angled or obcompressed- 

 plants with thick balsamiferous taproots 

 Pappus none; stem scapiform or with reduced leaves. 

 T, , ^ , „ 71. Balsamokhhiza. 



Pappus a lacerate chaffy crown or of distinct squamellae- 

 stem low but leafv. 72 Wyetiii\ 



Raj-s sterile or wanting: plants not with fleshy taproot 

 Pai)piis none or a minute ring. 67. Gi-MNOLOMii 



Pappus of 2 scarious awns. 73. Helivxthus 



Achenes of the disk thin-edged, margined or \yinged 

 Ray-flowers neutral; achenes scarcely winged. 



Pappus none or an awn to each angle of the achenes. 



Pappus of small teeth between the 2 or more awns or scales 

 over the angles of the achenes. 

 Plants scapose; achenes with a calloiLs margin. 

 ■D^ i. , J. , "5. Encehopsis. 



Plants catilescent; achenes not margined. 



76. Helianthella. 



