446 
The Ohio Naturalist. 
[Vol. XV, No. 4, 
1. Flowers yellow. 2. 
1. Flowers red, purple, or white. 4. 
2. Leaflets all sessile, stipules linear. T. agrarium. 
2. Terminal leaflet stalked, stipules ovate. 3. 
3. Heads 20-40 flowered. T. procumbens. 
3. Heads 8-15 flowered. T. dubium. 
4. Inflorescence much longer than thick; calyx silky, its teeth plumose. 5. 
4. Inflorescence a globose, oval, or ovoid head. 6. 
5. Leaflets ovate or orbicular; corolla crimson, as long or longer than 
the calyx. T. incarnatum. 
5. Leaflets linear or oblanceolate; corolla -whitish, shorter than the 
calyx. T. arvense. 
0. Flowers sessile or nearly so, in dense ovoid oval, or globose heads. 7. 
6. Flowers pedicelled in loose, globose, umbel-like heads. 8. 
7. Heads sessile or nearly so, having a leaf immediately below; stem 
hairy, especially when young. T. pratense. 
7. Heads always with a distinct peduncle, stem smoothish. T. medium. 
8. Leaflets narrowly oblong, plant villous; calyx silky, perennial. 
T. virginicum. 
8. Leaflets oval or obovate. 9. 
9. Calyx villous or with bristly hairs. 10. 
9. Calyx essentially glabrous. 11. 
10. Calyx-teeth herbaceous, deltoid-lanceolate, nearly equaling the 
corolla. T. carolinianum. 
10. Calyx-teeth bristle tipped, shorter than the corolla. T. reflexum. 
11. Heads 1 in. or more in diameter; peduncles usually 1-2 in. long’ stolo- 
niferous. T. stoloniferum. 
11. Heads X -% in. in diameter; peduncles 2-10 in. long. 12. 
12. Ascending, not stoloniferous; peduncles less than 6 in. long; flowers 
pink or nearly white. T. hybridum. 
12. Creeping, stoloniferous, peduncles usually more than 6 in. long; flowers 
white or pinkish. T. repens. 
1. Trifolium agrarium L. Yellow Hop Clover. 
Annual; ascending; 1X _ 2 ft. high; leaves 1 X in. long, 1 X in. 
wide; leaflets X in. long, X in. wide, obovate or oblong, den¬ 
ticulate, rounded at the apex, narrowed at the base; peduncles 
axillary, 1 in. long; flowers in oblong heads; corolla yellow, becom¬ 
ing dry and brown with age. Along roadsides and in waste 
places. Ashtabula, Lake, Cuyahoga, Knox, Clermont. From 
Europe. 
2. Trifolium procumbens L. Low Hop Clover. 
Spreading or ascending; pubescent; stem 1-1X ft. high; 
leaves 1-2 in. long, Li in. wide, petioled; leaflets X in. long, 
y\ in. wide, obovate, cuneate at the base, rounded at the apex, 
finely denticulate; peduncles IX in. long; flowers yellow, heads 
20—10-flowered. In fields and along roadsides. Lake, Cuyahoga, 
Ottawa, Franklin, Montgomery, Gallia. From Europe. 
3. Trifolium dubium Sibth. Least Hop Clover. 
Spreading or ascending; 10 in. high; leaves X in. long, X in. 
wide, petioled; leaflets X in. long, X in. wide, obovate, rounded 
at the apex, denticulate, cuneate at the base; peduncles X in- 
long; heads 8-15-flowered; flowers turning brown with age. 
In fields and waste places. Lake County. From Europe. 
