62 COMPOSIT.E. 



coriaceous oval or obovate concave bracts with short and abrupt foliaceons tips, subtending 

 the fertile flowers. Bracts of the receptacle all firm-coriaceous and persistent, linear or 

 lanceolate, partly enclosing the sterile tlowers or their pedicel-like inane ovary. Ligules 

 oblong, almost entire : disk-corollas narrowly funnelform, .5-lobed. Sterile style somewhat 

 clavate, very hispid. Akenes filling nearly the whole deeply concave face of tlie subtending 

 bract (not adnate to it), and covered by the 2 or 3 rigid internally attached chaffy bracts of 

 sterile flowers, obovate, wingless, both faces carinately uuicostate : indurated ba.ses of the 

 bract, the chaff, and the akene firmly and inseparably united, tardily falling away from the 

 receptacle. Pappus a conspicuous and persistent fii-m-scarious and hispid crown, m.ore or 

 less cleft into 3 or 4 irregular lobes or into a pair of lanceolate scales ; that of the abor- 

 tive ovaries somewhat similar but rudimentary, nearly as in Silphium. Alternate-leaved 

 perennial. 



++ ++ Heads small, mostly hemispherical, nearly or quite discoid ; the corolla of the 5 to 8 

 female flowers with the ligule verj' short, often broader than long, or obsolete : receptacle 

 conical or convex : flowers whitish : corollas of the sterile ones tubular-funnelform, and the 

 style glabrous except the more or less dilated and truncate pubescent summit, tlieir ovary 

 obsolete : akenes more turgid dorsally : involucre of i-ather few ovate or orbicular appressed 

 liracts, in about two series : leaves alternate. 



75. PARTHENIUM. Fertile flowers 5, with obcordate or 2-lobed almost sessile concave 

 ligule l)arely surpassing the disk, or a truncate emarginate cup. Bracts of the involucre 

 chartaceous or partly herbaceous, and the inner more scarious : those of the usually conical 

 receptacle cuneate, tomentose at summit, partly enclosing the sterile flowers. Akenes oval 

 or obovate, commonly pubescent, surrounded by a filiform callous margin, wliich is firmly 

 coherent at base with the bases of the bracts of the contiguous pair of sterile flowers and of 

 the subtending bract, at length tearing away from the akene ; the summit bearing the mar- 

 cescent corolla, and a pappus of two chaffy awns or scales, or sometimes hardly any. 



76. PARTHENICE. Fertile flowers 6 to 8, with corolla hardly equalling the disk, not 

 longer than the style, an obliquely cleft tube, with ligule obsolete or reduced to 2 or 3 small 

 teeth ; sterile flowers 40 or 50, with funnelform corolla. Involucre of .5 somewhat herba- 

 ceous oval exterior bracts, and of 6 or 8 somewhat larger orbicular-obovate and more 

 scarious interior ones, these subtending the fertile flowers. Receptacle convex, with linear- 

 oblong or spatulate chaffy bracts subtending the outer series of sterile flowers, but mostly 

 minute or wanting to the inner flowers. Akenes oblong-obovate, glabrous, wingless, but 

 acute-margined, with an incurved apiculation terminated by a small sphacelate obtuse tip, 

 inserted by a very small base, falling away at maturity with the invokicral and two recep- 

 tacular bracts, but these readily separating. Pappus none ; and corolla deciduous. 



Subtribe III. Ambrosie.e. Fertile flowers apetalous, or with corolla reduced to a ttibe 

 or ring around the base of the 2-parted style : disk-flowers staminate, with funnel- 

 form or obconical 4-5-lobed corolla, anthers slightly united and theii' short terminal 

 appendage inflexed, the abortive style hairy only at the somewhat enlarged and 

 depressed summit, the ovary a mere rudiment. Pappus none (or a vestige in Oxy- 

 tenia and Dicoria). Heads small; the flowers whitish or greenish. 



* Head androgynous (rarely all male in Dicor/a), having few (or rarely solitary) female 

 flowers at the margin ; the more numerous male flowers all or most of them subtended 

 by slender and commonly spatulate chaffy bracts : anther-tips short and obtuse, rarely 

 pointed : involucre open : akenes usually large for the size of the head, fi-ee. — Tre<e, DC. 



-1— Akenes turgid, mostly obovate or pyriform, marginless : dilated summit of the sterile 

 style hispidulous or radiately penicillate. 



77. IVA. Female flowers 1 to 5, with or without the tube or cu]) representing a corolla. 

 Akenes more or less obcompressed, glabrous, puberulent, or glandular ; the terminal areola 

 small. 



78. OXYTENIA. Female flowers about 5, wholly destitute of corolla; their style with 

 2 oval or oblong and very obtuse stigmatic lobes. Involucre of about 5 coriaceo-herl)aceous 

 dilated-ovate and rather rigidly acuminate bracts. Receptacle convex, small ; tlie 10 to 20 

 sterile flowers subtended by slender chaffy bracts with cuneate-dilated tips, or these wanting 

 to the central ones. Akenes (immature) obovate and turgid, very villous, nearly pyriform 



