FLOWERING PLANTS AND FERNS OF ARIZONA <S7 1 



4. Pappus none or vestigial C. 



4. Pappus evident on some or all of the achenes (5). 



5. Achenes with a pappus of awns or scales (paleae, squamellae) or both, 



these sometimes united into a low chaffy crown D. 



5. Achenes with a pappus of capillary bristles, rarely with additional 



outer scales E. 



3. Rays present but sometimes small (6). 



6. Pappus of capillary bristles, rarely with a few short outer scales F. 



6. Pappus none, or of awns or scales (7). 



7. Achenes without pappus, or the pappus vestigial G. 



7. Achenes (some or all of them) with a pappus of awns, or scales, or both, 

 these separate or united into a crown H. 



Key to the genera 



A. Corollas of some or all of the flowers bilabiate. 



1. Flowers at the margin of the head pistillate and with strap-shaped 3-toothed 

 corollas, the other flowers perfect and with bilabiate corollas; plants 



scapose 121. Chaptalia. 



1. Flowers all perfect and with bilabiate corollas; stems leafy (2). 



2. Plants herbaceous; corollas pink or whitish: involucre strongly graduated. 



122. Perezia. 

 2. Plant shrubbv; corollas vellow: involucre in onlv 2 distinct series. 



123. Trixis. 



B. Flowers all hermaphrodite and with strap-shaped 5-toothed corollas. 



1. Achenes without pappus 125. Atrichoseris. 



1. Achenes with pappus (2). 



2. Pappus, at least in part, of plumose bristles (3). 



3. Phyllaries in several strongly graduated series, very obtuse, broadly 

 scarious-margined; receptacle chaffy; flowers yellow. 



128. Axisocoma. 



3. Phyllaries not in several graduated series but often with a much shorter 



outer series, not, or narrowly, scarious-margined; receptacle naked (4). 



4. Achenes truncate at apex; plants more or less rushlike; corollas pink. 



130. Stephaxomeria. 

 4. Achenes tapering or beaked at apex (5). 



5. Plant scapose; leaves hispid; corollas yellow 129. Leoxtodox. 



5. Plants leafy-stemmed; leaves not hispid (6). 



6. Leaves pinnatifid; corollas white or pinkish; involucre with an 



outer series of short bractlets 131. Nemosebis. 



6. Leaves grasslike, entire; corollas yellow or violet purple; involucre 



without short outer bractlets 132. Tragopogox. 



2. Pappus of nonplumose bristles or of awns or scales (7). 

 7. Pappus, at least in part, of awns or scales (8). 



8. Corollas blue; plant with leafy branched stems 124. Cichorium. 



8. Corollas yellow or orange (9). 



9. Plants scapose or subscapose; pappus simple, of bifid paleae tipped 



with a bristle 126. Microseris. 



9. Plants caulescent, the stems few-leaved: pappus double, the outer 

 series of thin short scales, the inner series of much longer bristles. 



127. Krigia. 

 7. Pappus of capillary bristles only (lOh 



10. Achenes more or less flattened; stems leafy; heads in panicles (11). 

 11. Involucre campanulate or hemispheric; achenes not beaked. 



138. Sonchus. 



11. Involucre cylindric or ovoid-cylindric; achenes beaked. 



139. Lactic a. 

 10. Achenes not flattened (12). 



12. Achenes not beaked (13). 



13. Pappus quickly deciduous, or with 1 to 8 stiff persistent bristles; 



plants annual 134. Malacothrix. 



13. Pappus persistent (14). 



14. Plants rushlike or spinescent; corollas pink. 



140. Lygodesmia. 



