Genus 46. 



THISTLE FAMILY. 



457 



46. ADENOCAULON Hook. Bot. Misc. 1 : 19. 1830. 



Perennial herbs, with broad alternate slender-petioled leaves, woolly beneath, and pani- 

 cled small 5-10-flowered heads of tubular flowers. Involucre campanulate, composed of a 

 few herbaceous bracts. Receptacle nearly flat, naked. Corollas all tubular, 4-5-lobed. Mar- 

 ginal flowers pistillate, fertile. Central flowers perfect, sterile, the style undivided ; anthers 

 slightly sagittate at the Dase. Pappus none. Achenes obovoid or clavate, very obtuse, faintly 

 nerved, glandular above, longer than the bracts of the involucre. [Greek, gland-stem.] 



Two species, natives of North America, Japan and the Himalayas. Only the following typical 

 one is known in North America. 



i. Adenocaulon bicolor Hook. Adenocaulon. 

 Fig- 4415- 



Adenocaulon bicolor Hook. Bot. Misc. 1 : 19. pi. 15- 1830. 



Stem floccose-woolly, or at length glabrous, I-3 

 high, leafless and mostly paniculately branched above. 

 Leaves all basal or nearly so, deltoid-ovate, obtuse or 

 acute at the apex, deeply cordate at the base, coarsely 

 repand-toothed or lobed, thin, green and glabrous above, 

 densely and persistently white-woolly beneath, 2'-6' 

 long and broad, with slender narrowly margined peti- 

 oles; heads numerous, very slender-peduncled, small; 

 bracts of the involucre 4 or 5, ovate to lanceolate, re- 

 flexed in fruit, at length deciduous; achenes 3"-4" 

 long, i" thick, the upper part beset with nail-shaped 

 glands. 



In moist woods, northern Michigan and Lake Superior to 

 British Columbia, Montana and California. May-July. 



47. INULA L. Sp. PI. 881. 1753. 



Perennial, mostly tomentose or woolly herbs, with alternate and basal leaves, and large 

 heads of both tubular and radiate yellow flowers. Involucre hemispheric or campanulate, 

 its bracts imbricated in several series, the outer often foliaceous. Receptacle flat or convex, 

 areolate or foveolate, not chaffy. Ray-flowers pistillate, their ligules 3-toothed. Disk-flowers 

 perfect, their corollas tubular, 5-toothed. Anthers sagittate at the base, the auricles caudate. 

 Style-branches of the disk-flowers linear, obtuse. Achenes 4-5-ribbed; pappus of capillary 

 rough bristles in our species. [The ancient Latin name.] 



About 90 species, natives of Europe, Asia and Africa, the following typical. 



1. Inula Helenium I.. Elecampane. 

 Horseheal. Fig. 4416. 



Inula Helenium L. Sp. PI. 8S1. 1753. 



Stems tufted from large thick roots, simple 

 or rarely somewhat branched, 2-6 high, 

 densely pubescent above. Leaves large, broadly 

 oblong, rough above, densely pubescent be- 

 neath, denticulate, the basal ones acute at each 

 end. long-petioled, io'-2o' long, 4'S' wide; 

 stem leaves sessile, or cordate-clasping at the 

 base, acute at the apex, smaller; heads solitary 

 or few, terminal, stout-peduncled, 2'-4' broad ; 

 involucre hemispheric, nearly i' high, its outer 

 bracts ovate, foliaceous, pubescent ; rays nu- 

 merous, linear; achenes 'glabrous, 4-sided. 



Along roadsides and in fields. Nova Scotia to 

 Ontario and Minnesota, south to North Carolina 

 and Missouri. Naturalized from Europe. Native 

 also in Asia. Scabwort. Horse-elder. Yellow star- 

 wort. Elfdock. Elfwort. Wild sunflower. 



