COxMPOSlTAE (COMPOSITE FAMILY^ 797 



++ ++ Leaves somewhat folded, entire, the lower slightly Z-nerved. 



48. S. Riddellii Frank. Smooth and stoiit, 0.5-1 m. high, vei'y leafy, the 

 branches of the dense corymb and pedicels rough-pubescent ; leaves linear-lan- 

 ceolate, thr- cauline elongated (1-1.5 dm. long), acute, partly clasping or sheath- 

 ing, mostly recurved, the lowest elongated-lanceolate (8-o dm. long) and tapering 

 into a long keeled petiole ; heads very numerous, clustered, 20-oO-liowered ; rays 

 7-1). — Wet grassy prairies. Ont. to Minn, and Mo.; Ft. Monroe, Va. Atig., 

 Sept. — Heads larger than in the preceding. 



49. S. Houghtonii T. & G. Smooth ; stem rather low and slender, 3-6 dm. 

 high; leaves scattered, linear-lanceolate, arutish, rough-margined, 0.5-1.3 dm. 

 long, 5-10 mm. wide, tapering into a narrowed slightly clasping ba.se, 1-nerved, 

 or the lower 3-nerved and with margined petioles; veins obscure; heads few or 

 several, 20-oO-flowered ; involucre 6-8 mm. long, with obtuse bracts ; rays 7-9. 

 — Swamps, north shores of Lakes Michigan and Huron; Genesee Co., N. Y. 

 July, Aug. 



§2. EUTHAmIA Xutt. Corymhosely mnch branched ; heads small, sessile or 

 svbsessile, in little clusters crowded in flat-topped corymbs; the closely 

 apjpressed involucral bracts somewhat glutinous ; receptacle fimbrillate ; 

 rays 6-20. short, more numerous than the disk-flowers ; leaves narrow, 

 entire, sessile. 



* Leaves distinctly o-o-ribbed ; heads 2()-^f()-floioered. 



■<- Livolucre 4-5 mm. long, the bracts usually vithottt conspicuous tips. 



50. S. graminifolia (L.) Salisb. Stem 5-10 dm. high, glabrous; leave? 

 lance-linear, the primary ones 5-13 cm. long. 4-0 mm. broad, glabrous except 

 for the scabrous margins and the minutely pubescent nerves beneath ; branches 

 of the inflorescence glabrous or at most minutely serrulate on the angles ; leafy 

 bracts of the inflorescence ascending ; heads obovoid-cylindric, sessile, in dense 

 corymbed glomerules ; involucral bracts straw-color or yellowish-green, their 

 tips rarely darker, the outermost ovate or oblong. (Euthamia Nutt.; S. lanceo- 

 lata Man. ed. 6, and perhaps L.) — Moist soil, e. Que. to Sask., s. to N. J., 111., 

 Mo., and along the mt-s. to N. C. Aug.-Oct. 



Var. Nuttallii (Greene) Fernald. Leaves more pubescent ; branches of the 

 inflorescence hirtellous. — X. S. to Mich, and Ala. 



-»- •*- Invejlucre 3-3.5 mm. long, the bracts with conspicuous green tips. 



51. S. polycephala Fernald. Similar to the preceding variety; leaves 

 elongate, tliiu, puberulotis ; branches of the corymb very hirtellous, their 

 small bracts wide-spreading etr deflexed; involucre turbinate, very small, its 

 somewhat puberulent bracts with closely appressed deltoid green tips. — Apparently 

 local, s. N. J. and e, Ta. Aug., Sept. 



* * Leaves \-ribbed or obscurely S-nerved ; heads l'2-2()(i'arely 22)-flowered. 



-t- Leaves almost acicular, the middle cauline 1-1.5 mm. wide. 



52. S. minor (Michx.) Fernald. Very slender, 4-8 dm. high, the glabrous 

 stem freely fastigiate-branched above the middle ; leaves extremely slender, 

 the primary ones 3-5 cm. long, acerose-tipped, ^-ribbed, punctate, commonly 

 S2ibtending axillary fascicles as do many of the rameal ones; heads mostly short- 

 pedAce1(d, in numerous small corymbs ; invejlucre nearly cylindric, acute at base, 

 3-4 mm. long. 1-1.5 mm. thick, its firm appre.ssed glutinous straw-colored 

 bracts with slightly green acutish tips. {S. tenuifolia Pursh, in part.) — Sandy 

 soil, near the coast, Va. to Fla. and Ala. Sept., Oct. 



•^ -»- Leaves fleit, broader, 2-6 mm., idde. 



■^ Involucre 3-4 mm. long. 



53. S. tenuifblia Pursh. Rather slender, 3-9 dm. high, the glabrous stem 

 freely fastigiate-branclu-d above the middle ; leaves linear or linear-lanceolate, 

 soon spreading or reflexed ; the primary oiij's 4-7 cm. long, 2-4 mm. broad, 

 taper-pointed, 1-ribbed, often obscurely 2-nerved, minutely punctate, usually 



