STANDLEY TEEES AND SHEUBS OF MEXICO 1409 



Rays not papery-persistent. 



Achenes distinctly compressed, 2-nerved. 



Achenes ciliate; pappus of squamellae and usually 1 or 2 awns, rarely 

 wanting 90. PERIT YLE. 



Achenes not distinctly ciliate; pappus (in our species) of 1 awn, or wanting. 



91. LAPHAMIA. 

 Achenes not distinctly compressed, with more than 2 nerves. 

 Involucre glandular-punctate or glandular-lined. 



Pappus of 5 to 20 paleae, these often aristate-dissected or awned. 



99. DYSSODIA. 

 Pappus setose, the setae sometimes reduced to squamellae. 



Heads discoid 100. POROPHYLLUM, 



Heads radiate. 



Leaves not setose-ciliate; style branches elongate. 



101. CHRYS ACTINIA. 



Leaves setose-ciliate; style branches short 102. PECTIS. 



Involucre not glandular-punctate or glandular-lined. 



Achenes 10-ribbed; pappus none; heads 2 to 8-flowered, aggregated. 



92. FLAVERIA. 

 Achenes not 10-ribbed, usually 4-ribbed; pappus present; heads with 

 more numerous flowers, not aggregated. 



Pappus of 4 awns alternating with 4 squamellae 93. EUTETRAS. 



Pappus otherwise. 



Heads radiate, yellow. 



Phyllaries about 5; heads in small umbelliform cymes or cymose 

 panicles; achenes without substipitiform base. 



95. ERIOPHYLLUM, 

 Phyllaries more numerous; heads solitary or cymose-panicled; 



achenes with substipitiform base 97. BAHIA^ 



Heads discoid, white, flesh-color, or ochroleucous. 



Pappus oblique, of about 8 paleae, the innermost longest; 

 leaves opposite, broad, crenate or repand. 



98. LOXOTHYSANUS. 

 Pappus not oblique; leaves alternate, linear or pinnatilobate. 

 Pappus of 4 to 6 truncate paleae; leaves linear, entire. 



94. PALAFOXIA. 

 Pappus of about 13 acutish paleae; leaves pinnatilobate. 



96. CHAENACTIS. 

 Tribe VII. Anthemideae. 



A single genus 103. ARTEMISIA. 



Tribe VIII. Senecioneae. 

 Involucre distinctly graduate. 



Leaves opposite, not scalelike 104. LIABUM, 



Leaves alternate, all except the lower scalelike 105. LEPIDOSPARTUM. 



Principal phyllaries equal, sometimes with a series of small bractlets at base. 



Phyllaries 4 or 5, broadly oval; leaves opposite 106. HAPLOESTHES. 



Phyllaries more numerous; leaves alternate. 



Phyllaries caudate-attenuate, herbaceous above; involucre without bractlets 



at base; leaves glandular-punctate 107. PETJCEPHYLLUM. 



Phyllaries neither caudate-attenuate nor herbaceous; involucre bracteolate 

 at base; leaves not glandular-punctate 108. SENECIO. 



