THISTLE FA.MILY 837 



Receptacle not chaffy; style or style- branches of the hermaphrodite flowers mostlv 



truncate. 



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



center. 



Pappus-bristles of the pistillate flowers falling off in a ring; central liermaph- 

 rodite flowers none. 55. Axtennaria. 



Pappus-brMles of the pistillate flowers falling off separately; central hermaph- 

 rodite flowers present in the pistillate heads. 56. Anaphalis. 

 Plants not dioecious; flowers fertile tln-oughout the heads, hermaphrodite in the 



middle, surrounded by pistillate ones. 57. GiVAPHALrinw . 



Tribe 5. ADENOCAULEAE. 



m 



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



Tribe 6. HELIANTHEAE- 



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



glandular-viscid. 



I. Disk-flowers hermaphrodite but sterile. 



Marginal pistillate flowers, with conspicuous .rays, 



Achenes not flattened; ligules in oui-s white; involucres of very dissimilar sets 



of bracts. 59. MELAAiromUM. 



Aciienes flattened; ligules in ours yellow. 



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



60. SiLPHIUM. 

 Eay-flowers hi 1 series; achenes adnate to 2 or 3 paleae and falling awav 

 with them. 61. Engelmaxnia. 



:Marginal pistillate flowers reduced to a truncate or obliquely -cleft tube; the 



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

 Acauiescent cespitose perennials; pappus of a pair of lanceolate membranous 



scales. 62. Bolophyta. 



Caulescent annuals; pappus none. 63. Parthenice. 



II. Disk-flowers feitile. 



* a. Ray-flowers fertile; the Ugifles with very short tube, persistent on the achenes 



and becoming papery in texture. 

 Achenes of the disk compressed ; leaves entire. 64. Crassixa, 



Achenes obtusely 4-angIed. 



Leaves toothed; paleae pointless, partly enclosing the achenes. 



65. Heuopsis. 

 Leavesentire;paleaelinear-Ianceolate,notenclosing theachenes, (§ Kalliac- 

 lis, i. e., B. Careyana, of) 71. Bai^amorrhiza. 



b. Ray-corollas deciduous from the achenes or wanting. 



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



and rarely minute ones between. 

 a. Achenes of the disk-flowers not obcompressed (except in Ratibida and 



Ximenesia): paleae usually more or less concave and clasping. 

 Receptacle conic, subulate or columnar. 



Achenes 4-angled. 



Ray-flowers pm'plish or rarely whitish: disk-corollas almost 



without a tube; pappus coroniform. 66. Brau.veria. 

 Ray-flowers yellow or none; disk-corollas with a short but mani- 

 fest tube. 

 Acbenes quadrangular-compressed; apex of the achenes 

 covered by the base of the corolla-tube. 



67. Gymxot^mia. 

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

 base of the corolla. GS. Rudbeckia. 



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



Achenes flattened, broad-margined or winged. 



• 69. Ratibida. 



Receptacle from flat to convex. 



Aciienes of the disk neither sharp-angled, margined, nor winged. 

 Rays fertile, their achenes comnionly 3-angled or obcompressed ; 



plants with thick balsajjiiferous taproots. 

 Pappus none; stem scapiform or with reduced leaves. 



71. Balsamorrhiza. 



Pappus a lacerate chaflfy crown or of distinct squamellae; 

 stem low but leafy. 72. Wyethia. 



Rays sterile or wanting; plants not with fleshy taproot. 

 Pappus none or a minute ring. 67. G'i'MXOLOMTA, 



Pappus of 2 scarious awns. 73. Helianthijs. 



Achenes of the disk thin-edged, margined or winged. 

 Ray-flowers neutral; achenes scarcely winged. 



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



74. Encelia. 

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



over the angles of the achenes. 

 Plants scapose; achenes with a callous margin. 



75. Enceuopsis. 

 Plants caulescent; achenes not margined. 



76. Heliaxthell.v. 



