294 COMPOSITE. 



* * * Eay-akenes obcompressed or clavate, completely enclosed iu the involucral scales, which 

 are at base liattish on the back with their thin margins abruptly infolded. 



58. Lagophylla. Head few-flowered : ray-akenes about 5, obovate, much obcompressed, smooth. 



Disk-flowers infertile : pappus none. 



59. Layia. Head many-flowered : rays 8 to 20, with obovate or somewhat clavate smooth 



akeues. Disk-flowers or most of them fertile, their similar or narrower akenes often 

 pubescent : pappus composed of bristles (either plumose below or naked) or of subu- 

 late-pointed scales, or sometimes none. 



60. Achyrachaena. Head many-flowered ; the flowers all fertile. Akenes linear-cuneate or 



clavate, 10-ribbed, some or all the ribs tuberculate-scabrous ; those of the disk with a 

 pappus of blunt silvery-scarious chatfy scales in two series, the inner as long as the 

 corolla. 



Tribe VI. HELENIOIDEiE. Heads heterogamous with ligulate ray-corollas, or discoid 

 and homogamous by the absence of rays : the tubular disk-flowers perfect and fertile or 

 rarely sterde. Receptacle never chaffy (in one or two cases with awn-like bodies resem- 

 bling chaff). Anthers without tails. Branches of the style in perfect flowers either trun- 

 cate or tipped with an appendage. Pappus of several chaffy scales or sometimes of awns 

 or rigid bristles, not rarely wanting. Leaves opposite, or all but the lowest alternate. 

 Involucre of herbaceous or membranaceous scales, in one or two or rarely 3 or 4 series. 

 CoroUas most commonly yellow, both in disk and ray. 



Subtribe I. JAUMIE^E. Involucre of broad scales regularly imbricated, the outer succes- 

 sively shorter, destitute (as also the herbage) of oil-gfands. Akenes narrow, angled, in ours 

 destitute of pappus. Rays deciduous from the akenes. 



61. Jaumea. Involucre campanulate. Leaves opposite, connate at base, narrow, fleshy. 



62. Venegasia. Involucre very broad. Leaves alternate, ovate or cordate, membranaceous, 



long-petioled. 



Subtribe II. RIDDELLIE^. Involucre of narrow equal scales. Rays persistent on the 

 akenes, becoming papery. No oil-glands. Plants more or less white-woolly. 



* Pappus of chaffy scales : rays very broad and few. 



63. Riddellia. Head several-flowered ; the 3 or 4 rays broader than long, few-nerved, raised on 



a short slender tube, 3-lobed. Leaves alternate. 



* * Pappus none : rays 5 to 50. 



64. Baileya. Rays destitute of a tube, 7-nerved. Akenes many-striatc, all fertile. Receptacle 



nearly flat. Leaves opposite. 



65. Whitneya. Rays with a short tube, 10-16-nerved. Akenes few-nerved, those of the disk 



sterile. Receptacle conical. Leaves opposite. 



Subtribe III. HELENIEJI. {Bczricce, & Ewhcleniece, Benth.) Involucre of nearly equal 

 or narrow scales in one or few series. Rays if any deciduous. No oil-glands. 



* Akenes linear or linear-cimeate, 4-angled or compressed, but not witli cartilaginous margins. 



HH Receptacle conical, convex, or in part of No. 67 & 68 flattish or flat : involucre of few or several 



erect appressed or united herbaceous scales. 



++ Rays few, very short and included : receptacle high-conical : leaves all opposite, entire. 



71. Lastheniain part. Involucre a many-toothed cup. , , , , r,^■^ 



66. BurrieUa. Involucre of 3 to 5 separate flat scales. Receptacle subidate or almost filiform. 



Akenes slender : pappus of 1 to 4 rigid awn-shaped scales. 

 ++ ++ Rays exserted and spreading. 

 67 B^ria. Receptacle high-conical and mostly acute, minutely muricate. Scales of the invo- 

 lucre separate, flat, in a single series. Akenes linear or linear-cuneate. Leaves all 

 opposite, entire or laciniate-pinnatifid. r i • 



68. Actinolepis. Receptacle convex or conical, or rarely almost flat. Scales ot the mvohicre 



wholly separate, beconung concave and involute around the ray-akenes. Anthers 

 tipped with a narrowish or very slender appendage. Akenes slender. Leaves opposite 

 or alternate. 



69. Bahia. Receptacle flat, convex, or obtusely conical. Scales of the involucre separate or 



T>artly united into a cup, not embracing any of the akenes. Rays entire or barely 

 toothed at apex. Akenes linear or oblong-linear, with large terminal areola : pappus 

 of lilunt nerveless scales, rarely wanting. Leaves opposite or mostly alternate, com- 

 monly lobed or divided. Ours all woolly plants. 



