272 COMPOSITAE. 



404. SOLIDAGO. GOLDENROD. 



Perennial herbs; leaves alternate; heads small, mostly in 

 panicles or panicled racemose clusters, radiate, the ray-flowers 

 fertile, yellow; involucre imbricated, the bracts usually without 

 herbaceous tips; pappus simple, of a single series of mostly equal 

 and slender scabrous capillary bristles; style-appendages lanceo- 

 late or triangular-subulate; akenes terete or angular, 5-12-ribbed. 



Leaves thick, the radical spatulate, much longer than the 



cauline. S. missouriensis. 



Leaves thinner, all alike. 



Heads 5-7 mm. high; panicle moderately dense. S. serotina. 



Heads 4-5 mm. high; panicle very dense. S. elongate. 



Solidago missouriensis Gray. Tufted, glabrous throughout, 20-60 cm. 

 high; radical and lower leaves thickish, spatulate-lanceolate, acute, entire or 

 obscurely serrate, 10-15 cm. long, sometimes 2 cm. broad; cauline linear or 

 lanceolate, often somewhat folded, 2-8 cm. long, with much smaller ones 

 fascicled in the upper axils; panicle pyramidal, 8-15 cm. long; heads 4-6 mm. 

 high, usually secund on the erect or recurved branches; rays 6-12, small; 

 bracts lanceolate, obtuse, the outermost much shorter. Hillsides, common. 



Solidago serotina Ait. Stems stout and tall, 100-150 cm. high, very 

 smooth below the inflorescence, the stem often glaucous; leaves lanceolate or 

 oblong-lanceolate, acuminate, prominently 3-nerved, and usually saliently 

 sharply-serrate, 6-15 cm. long, smooth on both sides; heads 5-7 mm. high, 

 crowded on the spreading often curved branches of the large pyramidal 

 panicle; bracts thin, linear, obtuse; rays 7-14, yellow; akenes pubescent. In 

 open copses along streams. 



Solidago serotina salebrosa Piper. Leaves harshly scabrous on both 

 surfaces, usually less serrate, otherwise like the species. Much commoner 

 than the species and in similar places. 



Solidago elongata Nutt. Very similar to S. serotina but stem green not 

 glaucous; panicle smaller, more compact; heads smaller; rays 12-20. Moist 

 places in open woods, Spokane County and adjacent Idaho. 



405. EUTHAMIA. 



Erect scabrous perennials with narrow alternate leaves; 

 flowers in numerous small heads in terminal flat-topped corym- 

 bose panicles; heads many-flowered, the ray-flowers yellow, 

 equalling and more numerous than the disk-flowers; receptacle 

 fimbrillate; akenes villous. 



Euthamia occidentalis Nutt. Glabrous; stems 90^-120 cm. high, erect, 

 branched above; leaves linear, entire, 3-nerved, the principal ones 5-10 cm. 

 long; heads peduncled, in small corymbs; involucral bracts narrow, acute; 

 rays 16-20. Frequent in wet places. 



406. ARNICA. 



Perennial herbs ; stems mostly simple, from creeping rootstocks 

 or a corm-like base; leaves all or some of them opposite, simple, 



