292 CUiMl'USlT.E. 



31. Stylocline. Fertile flowers 5 to 10 or minierous, in two or more series on a cylindrical or 



coliunniir rucf|ilaili« ; liieir clmtl" thin, siicciito or boat-shaped. Pappus of a lew cmlu- 

 cous bristles to tlie sterile Uowci-s, or uoiio. 



■+-+■ Chaff more open, subLending or hardly enclosing the fertile tlowers or their akenes, these in 

 more than one series : central llowers sometimes fertile. 



32. Evaz § Hksi'ekevax. Iteceptacle villous, its centre elongated into a narrow column. 



Akenes pear-shaped, llattish paiallcl to the subtending scale : pappus none. 

 83. Filago. Keceptacle obeonical or cylindraceous with a Hat summit. Akenes oblong, nearly 

 terete : pappus of numerous bristles to the perfect or sterile flowers, fewer or none to the 

 outer fertile Jlowers. 



Subtribe III. GNAPHALlEyE. Scales of the involucre all thin and scarious, often pearly, 

 persistent. Receptacle naked. FloccoSe-wooUy herbs. Flowers in all the American gen- 

 em with capillary |>ai)pus, nearly in a single series ; the pistillate ones with iilifonn or 

 very slender corollas. 



34. Antennaria. Heads completely dioecious ; the staminate with \individed style and bristles 



of tlie pappus thi.:kened or barbellate at the apex ; pistillate with slender bristles of the 

 pappus united at base into a ring. Low caispitose herbs. 



35. Anaphalia. Heads incom])letely dioecious ; i. e. the staminate ones with a few hennaphro- 



dite but sterile flowers m the centre. Style commonly 2-cleft at the apex. Bristles of 

 the papi)U3 all separate, those of the sterile flowers little thickened upward. Taller 

 herbs. 



36. Gnaphalium. llcinis all heterogamou.s, with ])istillate flowers very numerous in more than 



one series, and lu.rnuiphrodite fertile ones fewer in the centre. Hristles of pappus slen- 

 der, not thickeneil upward. 



Tribk V. HELIANTHOIDEzE. Heads heterogamous with ligulate ray-corollas, or discoid 

 and homogamous (or rarely heterogamous) ; the perfect or staminate flowers with tubular 

 regularly 4 - 5-lobed corollas. Receptacle chaffy (except sometimes among the disk-flow- 

 ers especially when sterile). Anthers often sagittate at base, but without tails. Branches 

 of the style in jjerlect llowers either truncate or tipped with an appendage. Pappus of 

 2 to 4 chaffy scales, awns, teeth, &e., or a cup or crown, never of capdlary bristles. Leaves 

 mostly opposite, at least the lower ones. Corollas most commonly yellow. 



Subtribe L AJiIBROSIEyE. Heads small and discoid : only the pistillate flowers fertile ; these 

 few and with no corolla, or a rudimentary one in the form of a short tube surrounding the 

 base of tho style. Hermaphrodite-sterile or staminate flowers with campanulate limb to 

 the corolla ; anthers .slightly cohering or nearly distinct, their inflexed tijis often mucro- 

 nate or cus[)idiite ; the abortive stylo entire, with truncate ajiex ti]>ped with a minute radi- 

 ate tuft or brush. l'ai)pus none. Akenes in our genera obovate and thick. 



* Heads heterogamous, a few fertile flowers at the margin. 



37. Oxytenia. Fertile flowers apetalous : akenes long-villous, crowned with a protuberant 



epigynous disk. Leaves pinnately divided, or the upper entire. 



38. Iva. Fertile flowers with short tubular corolla : akenes naked. Leaves simple. 



♦ ♦ Headi homogamous, unisexual, monrecious ; tho fertile with 1 to 4 jjistillato ajietalous flowers 

 in a closed ami Iturlike or akeiie-like pointed involucre ; sterile with rather numerous 

 flowers in an open 



-H 5-12-lobed or almost truncate involucre. 



39. Hymenoclea. Fertile involucre one-flowered, appendaged with 9 to 12 scarious spreading 



scales. Stem shrubby. 



40. Ambrosia. Fertile involucre one-flowered, akene-like, bearing no more than a suigle row 



of tiibercles or shoit spines. Herbs. 



41. Franseria. Fertile involucre 1 - 4-flowered, 1 - 4-celled, armed with more than one row of 



tubercles or prickles. 



+- +■ Involucre to sterile heads of a few distinct scales. 



42. Xanthium. Fertile involucre oblong, bur-like, 2-flowered, 2-celled, beset with numerous 



hooked prickles. 



Subtribe II. VKRIJESINEvE. Heads radiate, the rays either neutral or ])istillatc, or else ray- 

 less ; the disk-flowers perfect and fertile, each subtended by a chatf ot the receptacle. 

 Akenes thick and 3-4-angular; or those of the disk laterally compressed (i. e. contrary 

 to the subtending chafi"), never obcomjnessed (i. e. flattened jiarallel with the chafl'). 

 Pappus none, or a cup or crown, or of 2 to 4 rigid awns or chaffy scales from the angles, 

 with or without some intennediate small scales. 



