COMPOSITE. (COMPOSITE FAMILY.) 189 



62. Achillea. 1 Involucre with imbricated bracts as in the last, but campanulate or obo- 



vate. Chaffy bracts of the receptacle menibranaceous, like the innermost bracts of the 

 involucre. Rays few or several, short and broad. Akenes oblong or obovate, obcom- 

 pressed, glabrous, destitute of pappus. 



* * Receptacle destitute of bracts or chaff. 



- Heads radiate, pedunculate, solitary at the summit of the branches, or sometimes corym- 

 bose. 



63. Matricaria. 2 Receptacle conical or ovoid, or rarely lower when young. Akenes 3 to 



5-ribbed or nerved on the face or sides, rounded on the back. 

 - - Heads discoid. 



64. Tanacetum. Heads corymbosely cymose or glomerate, rarely solitary, many-flowered ; 



female flowers with tubular 3 to 5-toothed corolla. Akenes 5-ribbed or 3 to 5-angular, 

 with broad truncate summit, bearing a coroniform pappus or none. Anther-tips 

 broad and mostly obtuse. 



65. Artemisia. Heads paniculately disposed, few to many-flowered, small, heterogamous, 



the female flowers with small and slender tubular corolla, and the hermaphrodite 

 either sterile or fertile ; or homogamous, with the flowers all hermaphrodite and fer- 

 tile. Anther-tips slender and pointed. Akenes obovate or oblong, destitute of 

 pappus. 



Tribe VIII. SENECIONIDE^E. Involucre mostly one or two series of equal bracts, 

 sometimes unequal or imbricated, with or without accessory ones at base. Leaves 

 usually alternate. Chiefly distinguished by the copious capillary pappus, simple in- 

 volucre, and naked receptacle. 



* Involucre a series of soft herbaceous bracts : heads subdioecious, racemosely or corym- 



bosely disposed, whitish flowered : herbs with ample mostly radical leaves. 



66. Petasites. Akenes narrow, 5 to 10-costate, with elongating soft and white pappus. 



* * Involucre lax (not erect-connivent), of much overlapping bracts (4 or 5), many- (at 



least 20-) flowered : herbs with opposite leaves. 



67. Haploesthes. Heads radiate ; flowers all fertile. Involucre short-campanulate, of 



similar rather fleshy orbicular or broadly oval bracts, the outer strongly overlapping 

 the inner. Ligules of the rather few and short ray-flowers oval. Akenes linear, terete, 

 striate-costate, glabrous. Pappus a single series of rather rigid and scabrous whitish 

 bristles. 



* * * Involucre of 4 to 6 firm and concave close and strongly overlapping bracts, 4 to 9- 



flowered : shrubs, with alternate leaves. 



63. Tetradymia. Heads homogamous. Involucre cylindrical to oblong. Corollas with 

 lanceolate or linear spreading lobes. Anthers wholly exserted. Akenes terete, short, 

 obscurely 5-nerved, from extremely long-villous to glabrate or even glabrous. Pappus 

 of fine and soft minutely scabrous capillary long bristles, white or whitish. 



* * * * Involucre of numerous or several connivent-erect herbaceous equal bracts, many- 



flowered : herbs, with opposite or alternate leaves. 



69. Arnica. Heads conspicuously radiate, or the rays rarely wanting. Involucre cam- 

 panulate, of several thin-herbaceous oblong-lanceolate to linear equal bracts in a single 



1 The Old- World genus Anthemis has a naturalized species within our range and may be 

 characterized as follows : 



Anthemis. Involucre hemispherical, many-flowered, of comparatively small imbricated 

 bracts, the outer successively shorter. Chaffy bracts of receptacle sometimes hyaline, some- 

 times aristiform. Akenes terete or 4 to 10-angled or ribbed, not flattened, glabrous ; the 

 truncate summit naked, or with a very short coroniform or auriculate pappus. Heads 

 comparatively large See p. 198. 



2 The following Old- World genus has a naturalized species within our borders : 

 Chrysanthemum. Receptacle from flat to hemispherical. Akenes (at least of the disk) 



5 to 10-ribbed or nerved all round. See p. 199. 



