HULSEA— ISOCOMA 281 



2. Bracts of the involucre in 1 row with some short 

 basal ones ; stems naked or with few leaves 



a. Flowers white or yellowish 77. albiflorum 



b. Flowers yellow 



(1) Achenes tapering gradually to a narrow tip H. Fcndlcri 



(2) Achenes cylindric, not tapering above 



x. Involucres black-hairy H. grdctie 



y. Involucres white-hairy H. Scoulcri 



Hulsea Torrey and Gray 

 (Named for Hulse, an American physician) 

 Heads with yellow or purple ray-flowers, disk-flowers perfect, yellow, 

 achenes linear-wedge-shaped, flattened or somewhat 4-angled, hairy, pappus 

 of 4 scales ; receptacle flat, without chaff, involucre hemispheric with bracts 

 in 2-3 series ; flowers solitary as a rule ; leaves alternate, sessile, entire to 

 pinnatifid ; perennial. 



Plants fleshy; leaves lobed, 2-4 in. long; rays 7-9 mm. 

 long H. camosa 



Hymenopappus L'Heritier 1803 Hymenopappus 

 (Gr., hymen, membrane, pappos, pappus) 

 PI. 41, fig. 4. 

 Heads without rays, disk-flowers white to yellow, perfect, achenes 

 obovoid to long wedge-shaped, 4-5-angled, pappus of 10-20 scales, some- 

 times short or none ; receptacle flat, naked, involucre hemispheric to bell- 

 shaped, bracts 6-12 in 1-2 rows, usually colored, the margins papery; heads 

 solitary or in corymbs ; leaves alternate or basal, usually pinnatifid or dis- 

 sected ; perennial or biennial. 



Stems 4 in. to 2 ft. high ; leaves 1-3-pinnatifid, gray- 

 hairy or felted to green and nearly smooth ; corolla- 

 throat 2-4 times the length of the lobes ; pappus 

 scales of various lengths II. tenuifolius 



Isocoma Nuttall 1841 

 (Gr., isoSj equal, komc, tuft, perhaps from the pappus) 

 Heads without rays, disk-flowers yellow, perfect, achenes short, silky- 

 hairy, pappus of darkish hair-like bristles; receptacle flat, without chafT, 

 the bracts imbricated in several rows, often papery; heads in a corymb- 

 like cyme ; leaves simple, entire or somewhat deeply toothed, usually sticky ; 

 perennial, somewhat woody at base. 

 Stems 1-2 ft. high; leaves narrowly linear; heads 8- 



10 mm. high, 7-15 flowered /. Wrightii 



