COMPOSITE. 



297 



101. Senecio. Heads heterogamous and radiate, or homogamous. Disk-corollas 5-toothcd or 



5-lobed, mostly with slender tube. Pappus copious, fine and soft, white. 



* * Leaves mostly opposite or all radical : bristles of the pappus in a single series, rigid, strongly 



scabrous, barbellate, or plumose. 



102. Arnica. Heads heterogamous or occasionally homogamous. Pappus scabrous or barbellate. 



Leaves all or some of them opposite. 



103. Raillardella. Heads homogamous. Scales of the involucre slightly united below. Pappus 



strongly plumose, white. Leaves all radical, alternate. 



Tribe IX. CYITAROIDEiE. Heads homogamous and the flowers all perfect, with corollas 

 all tubular and deeply 5-cleft, often bilabiately so (J or §), or rarely incompletely dioe- 

 cious, sometimes (in introduced representatives) with a row of neutral flowers at the margin, 

 the corollas of which may be enlarged, fomiing a kind of false ray. Lobes of the corolla 

 not revolute. Receptacle generally densely bristly. Anthers sagittate, with their auri- 

 cles often prolonged into tails. Style destitute of all terminal appendages or tips ; the stig- 

 matic branches either short or slender, but mostly united to the apex or near it, minutely 

 puberulent or gi'anulate : at the origin the style is moi-e commonly thickened into a kind 

 of node or thickened and often pubescent ring. Akenes usually thick -walled. Pappus of 

 capillary or rigid bristles. Leaves alternate, the tips or lobes and teeth commonly armed 

 with prickles. Involucre often of spiny-tipped scales, imbricated in many series. — Only 

 Thistles are indigenous to the country, but one or two other genera have been introduced 

 from the Old World. 



* Flowers of the head all alike : bristles of the pappus cohering at base in a ring. 



104. Cnicus. Pappus plumose : filaments separate, papillose-pubescent. 



105. Silybum. Pappus naked : filaments monadelphous, glabrous. Leaves blotched. 



* * Flowers at the margin of the head mostly sterile : bristles of the pappus separate, not plumose. 



106. Centaurea. Akenes attached to the receptacle obliquely or by one side of the base. 



Tribe X. MUTISIACE.'E. Heads homogamous or sometimes heterogamous, with the limb 

 of the corollas bilabiate (§), one lip 3-, the other 2- toothed or cleft. Receptacle not 

 clothed with bristles. Anthers with long tails. Style-branches obtuse or truncate and 

 destitute of any tip or appendage. Leaves alternate. — Only one scanty Californian genus. 



107. Perezia. Head few - many-flowered : the flowers all perfect and similar, with distinctly 



2-lipped corollas. Involucre imbricated. Pappus of copious capillary bristles. Akenes 



beakless. 



Tribe XI. CICHORIACEiE. Heads homogamous, the flowers all perfect and with ligulate 

 corollas, the ligule 5-toothed at the apex. Style-branches filiform, papillose. Herbs (ex- 

 cept a few insular species) with milky bitter juice. — The subtribes, not being well-marked 

 by obvious characters, here give place to artificial sections. 



* Pappus none. All but No. 108 are genera which ordinarily have a pappus. 



108. Phalacroseris. Scape simple: head erect before flowering. Akenes obscurely 4-5- 



angled. 



109. Microseris, partly. Scape simple : head nodding before flowering. Akenes 10- ribbed. 

 116. Malacothrix § Anathrix. Scape corymbose-panicled : heads rather numerous. 



* * Pappus either chaffy or plumose, i. e. of awn-tipped chaffy scales, or of awns or bristles more 



or less dilated into a scale at base, or of plumose bristles. 



■i- Receptacle destitute of chaff or bristles : akenes more or less hollowed out at the insertion. 



109. Microseris. Flowers yellow. Akenes 8- 12-ribbed : pappus more or less chaffy. Stemless 



or shoi't-stemmed and long-peduncled, with head commonly nodding before flowering. 



110. Stephanomeria. Flowers pink or white. Akenes short, truncate at both ends, about 



5-ribbed or angled : pappus of plumose or partly plumose bristles, or rarely chaffy awns, 

 or narrow scales. Leafy-stemmed and branching, with small heads. 



111. Rafinesquia. Flowers white or pink. Akenes tapering upwards into a narrow beak, 



oljscurely ribbed : pappus of cobwebby-plumose slender bristles. Leafy-stemmed and 

 branching, with rather large heads. 



-i- -i- Receptacle with slender chaff between the flowers : akenes inserted by a pointed base : pap- 

 pus of plumose bristles : flowers yellow. 



112. Hypochaeris. Akenes glabrous, the inner ones at least tapering upwards into a beak : 



pappus sordid or dirty white. 



113. Anisocoma. Akenes silky-pubescent, truncate and with a little crown at the summit : 



pappus bright white. 



