Family ASTERACE 191 
1. Gaertneria acanthicarpa (Hook.) Britton. Bur-ragweed. 
In moist soil in the western part of the state. Crawford; Merriman; 
Porter. 
2. Gaertneria discolor (Nutt.) Kuntze. j 
In dry soil in the western part of the state. Dix. 
3. Gaertneria tomentosa (A. Gray) Kuntze. 
In low prairies along streams. Axtell; Franklin; Hastings; Minden. 
4, Xanthium. 911. 
Burs 15-25 mm. long, about half as thick or less. 
Prickles not hispid or scarcely so. 1. X. pennsylvanicum. 
Prickles hispid to about the middle. 
Leaves lobed; burs commonly solitary. 2. X. commune. 
Leaves dentate; burs commonly clustered. 3. X. speciosum. 
Burs 10-15 mm. long, 6-9 mm. thick, its prickles bristly-hispid 
nearly to the hooked apex. 4. X. glanduliferum. 
1. Xanthium pennsylvanicum Wallr. Cocklebur. 
Not common, most of our cockleburs belong to the next species. 
Kennedy; Red Cloud; Valentine. 
2. Xanthium commune Britton. Common Cocklebur. 
A common weed all over the state. Grand Island; Lincoln; Red 
Cloud; St. Paul; Valentine; Wahoo. 
3. Xanthium speciosum Kearney. 
Nebraska, according to Britton and Brown. 
4. Xanthium glanduliferum Greene. Glandular Clot-bur. 
Fremont; Long Pine; Nebraska City; Red Cloud; Whitman. 
Tribe 7. HELENIE. 
Bracts of the involucre petaloid with scarious tips and margins. 
Leaves pinnatifid; flowers white or yellow, rays none. 
1. Hymenopappus. 
Leaves entire; flowers purple, rays present or wanting. 2. Polypteris. 
Bracts of the involucre herbaceous. 
Leaves palmately divided into 2-5 narrow segments. 
3. Picradeniopsis. 
Leaves not palmately divided. 
Foliage not dotted with oil-glands. 
Receptacle naked, rays yellow. 
Bracts of the involucre appressed; leaves not decurrent on 
the stem. 4, Tetraneuris. 
Bracts of the involucre spreading or reflexed at maturity; 
leaves usually decurrent on the stem. 5. Helenium. 
Receptacle bristly, rays in our species purple, at least at the 
base. 6. Gaillardia. 
Foliage dotted with oil glands. 
Leaves dissected; involucral bracts partly united. 7. Boebera. 
Leaves entire, linear; bracts separate. 8. Pectis. 
1. Hymenopappus. 1006. 
Corolla white; heads 8-12 mm. broad; biennials. 
Achene puberulent; pappus shorter than the width of the achene. 
1. H. corymbosus. 
Achene densely villous; pappus as long as the width of the achene. 
2. H. tenuifolius. 
