COMPOSITE. 191 



equal ; the outer series often large and leafy. Receptacle flat- 

 tish, chaffy. Achenia obcompressed, not winged, crowned with 

 2 5 retrorsely pilose rigid awns. 



1. B. cernua Linn. : smooth; leaves undivided, lanceolate, toothed, the 

 upper somewhat connate ; heads discoid or radiate, on slender peduncles, 

 usually nodding ; outer involucre longer than the head ; achenia 4-awned. 

 retrorsely ciliate on the margin. 



Near ponds and ditches. Can. to Perm. W. to Oregon. Aug., Sept. (J). 

 Stem 1 2 feet high. Heads usually discoid, but sometimes more or less radiate ; 

 rays, when present, yellow. This plant is sometimes not more than 6 or 8 inches 

 high, with very small erect flowers, when it constitutes the variety minima. 



Swamp Beggar-ticks. 



2. H. chrysanthemoides Mich. : stem smooth ; leaves undivided, oblong- 

 lanceolate, tapering at each end, connate at base, dentate-serrate ; heads 

 radiate, somewhat nodding ; rays elliptic, longer than the involucre ; ache- 

 nia with 2 4 retrorsely scabrous awns. 



Wet places. Can. and throughout the U. S. Aug., Sept. .Stem 12 

 feet high, erect or declined at base, branching. Heads rather large, solitary at 

 the end of the branches, erect or somewhat nodding ; rays 8 10, bright yellow. 



Large-flowered Bur-marigold. 



3. B . frondosa Linn. : stem smoother a little hairy; lower leaves quinate- 

 pinnate, upper 3-parted ; the lobes lanceolate, serrate ; heads discoid, pedicel- 

 late, erect ; outer scales of the involucre much longer than the head, ciliate 

 at the base ; achenia 2-awned, somewhat ciliate on the margin. 



Woods and fields. Can. and throughout the U. S. July Sept. (p. Stem 

 2 5 feet high, stria te, often purple, branched. Heads rather email, on long axil- 

 lary branches or peduncles ; rays none ; disk flowers yellowish. 



Leafy Bur-marigold. 



4. B. connata Muhl. : smooth ; lower leaves often ternate, with the 

 lateral lobes decurrent into a petiole and slightly connate ; upper undivided, 

 oblong-lanceolate, serrate, attenuate at each end ; heads discoid, on short 

 peduncles ; scales of the outer involucre longer than the disk ; achenia 2 3- 

 awned. B. tripartita Big. 



Wet grounds. Can. to Geor. W. to Miss. July Sept. (). Stem 13 feet 

 high, branched, often purple. Leaves sometimes all undivided. Heads middle- 

 sized, rather erect ; rays none ; disk greenish-yellow. Connate Bur-marigold. 



5. B. bipinnata Linn. : smooth ; stem erect, 4-angled ; leaves petioled, 

 bi-pinnate, the segments lanceolate or oblong-ovate : heads on slender pe- 

 duncles, with 2 4 small rays; outer scales of the involucre speading. about 

 as long as the disk ; achenia linear, 3 4-awned. 



Near cultivated grounds. Conn, to Flor. W. to Ark. July Sept. CD Stem 

 2 4 feet high, branched. Heads small, oblong, on long terminal and axillary 

 peduncles ; rays 3 4, small, yellow, obovate ; disk yellow. A troublesome 

 weed, probably introduced from the South. Spanish Needles. 



0. B. Beckii Torr. : stem simple or sparingly branched ; leaves -mostly 

 submerged, divided into numerous capillary segments ; the emersed ones 

 few, lanceolate, coarsely serrate or pinnatifidly laciniate; heads solitary, 

 erect, radiate, terminal ; rays longer than the involucre ; achenia narrow- 

 oblong, 4 6-awned. 



