216 COMPOSITE. (COMPOSITE FAMILY.) 



74. MICROSERIS, Don. 



Glabrous or merely puberulent, acaulescent or subcaulescent ; with heads of 

 yellow flowers terminating naked scapes or elongated simple peduncles. 



* Pappus of 15 to 20 white and soft plumose bristles with chaffy base : akenes 



Unear<olumnar, of same diameter from base to summit: stems more or less 

 branching and leaf-bearing. 



1. M. nutans, Gray. Slender, a foot or so high : fusiform roots either 

 fascicled or solitary : leaves from entire and spatulate-obovate to pinnately 

 parted into narrow linear lobes: heads 8 to 20 flowered, slender-peduncled : 

 involucre of 8 to 10 linear-lanceolate gradually acuminate principal bracts : 

 bristles of pappus several times longer than the oblong scale at the base. — 

 Proc. Am. Acad. ix. 208. From British Columbia and Montana to S. W. 

 Colorado and California. 



* * Pappus of .20 to 24 narrowly linear-lanceolate silvery-white scales, occupying 



two or more series, very gradually attenuate into a slender awn: akenes attenu- 

 ate-fusiform. 



2. M. troximoides, Gray. Acaulescent or nearly so : leaves tufted on 

 the caudex, rather fleshy, narrowly linear-lanceolate, entire or undulate, 4 to 

 6 inches long : scapes a span to a foot high : involucre f inch high : pappus 

 h inch or more long, its almost setiform scales j line wide below. — Proc. Am. 

 Acad. ix. 211. Hills and open plains, Montana and Idaho to Washington 

 and California. 



75. MALACOTHRIX, DC. 



Leafy -stemmed or scapose ; with pedunculate heads of yellow or white 

 flowers, sometimes becoming purplish-tinged. In ours the involucre is of 

 narrow bracts and short-peduncled on the leafy spreading branches. 



1. M. sonchoides, Torr. & Gray. A span to a foot high : lower leaves 

 oblong, piunatifid, with short and dentate lobes, rhachis of the principal leaves 

 also dentate: akenes linear-oblong, 15-striate-ribbed, somewhat angled by 5 

 moderately stronger ribs, the summit with a 15-denticulate white border. — 

 Fl. ii. 486. Plains of W. Nebraska to New Mexico and westward. 



76. HIERACIUM, Tourn. Hawkweed. 



Perennial herbs : often with toothed but never deeply lobed leaves : heads 

 paniculate, rarely solitary : flowers yellow, or white in one species. 



§ 1. Involucre of the comparatively large heads irregularly more or less imbri- 

 cated: pappus of copious and unequal bn'stles: akenes columnar, truncate. 

 In ours the stems are leafy to the top, the cauline leaves all closely sessile. 

 1. H. umbellatum, L. A foot or two high, strict, bearing a few some- 

 what umbellate! '// disj>osed heads: leaves narrowly or sometimes broadly lanceo- 

 late, nearly entire, sparsely denticulate, occasionally laciniate-dentate, all narrow 

 at base : involucre usually livid, glabrous or nearly so ; outermost bracts loose 

 or spreading. — From Lake Superior to the Rocky Mountains, and northward. 



