434 THE KINDS OF PLANTS 



h. Plants cottony-white, or downy- 

 looking. 

 i Heads mostly dicecious. 



J. Leaves basal and also on stem: 

 pappus thickened at summit 

 and more or less barbed or 



plumed 31. Antennaria 



jj. Stems leafy: pappus not thick- 

 ened at summit: some sterile 

 flowers, usually in center of 



the fertile heads 32. Anaphahs 



II. Heads not dicecious: outer flowers 



pistillate, central perfect 33. Gnaphalium 



hh. Plants not cottony-white. 



I. Flower-heads showy, spicate or 

 racemed, rose-purple: leaves 



alternate 34. Liatris 



ii. Flower-heads small, in cymes or 

 corymbs, 

 j. Flowers white or pale purple: 



leaves mostly opposite 35. Eupatorium 



jj. Flowers purple: leaves alter- 

 nate 36. Vernonia 



1. TARAXACUM. Dandelion. 



Stemless herbs, the 1-headed scape short, leafless and hollow: florets 

 all perfect and strap-shaped: fruit ribbed, the pappus raised on a long beak. 

 Variable plants. 



T. officinale, Weber (T. Dens-leonis, Desf.). Common dandelion. Figs. 

 8, 302. Perennial, introduced from the Old World: leaves long, pinnate or 

 lyrate: heads yellow, opening in sun. 



2. TRAGOPOGON. Goat's Beard. 



Biennials or perennials, stout, smooth, often glaucous, with long, grass- 

 like leaves clasping the stem: flowers all ligulate, in large solitary heads, 

 purple or yellow, terminal on long peduncle, with single involucre of many 

 bracts, which are equal and lanceolate, joined at bases: pappus in one 

 series, long and plumose: achenes linear, mostly with long slender beaks, 

 5-10-ribbed or angled: flowers open in early morning, usually closed at 

 midday. Juice milky. 



T. porrifolius, Linn. Salsify. Oyster-plant. Biennial; involucral bracts 

 much longer than the rays: stems 2-3 ft. high, hollow and thickened 

 upward: flowers purple. Europe. Cultivated for the edible tap-root. Some- 

 times wild. 



T. pratensis, Linn. Similar to preceding, but flowers yellow and in- 

 volucral bracts not longer than rays. Europe. Fields and waste places, 

 eastern and middle states. 



