LEGUMINIFERZ. 51 
ated, and not shrivelling after flowering. Pod about as long as 
the calyx-tube. Seeds 2, often reduced to 1 by abortion. 
The smoothness of the plant, the globular heads, the shorter 
calyx-teeth enlarged immediately above the base, and the purplish 
flowers readily distinguish this plant from T. scabrum. 
Smooth Round-headed Trefoil. 
French, T'réfle Aggloméré. 
SPECIES XIIL—TRIFOLIUM SUFFOCATUM. Linn. 
Puate CCCLIX. 
Rootstock none. Stems numerous, prostrate, simple or slightly 
branched, the central one extremely short. Leaves on very long 
stalks ; leaflets wedgeshaped-obovate, truncate or emarginate 
at the apex, denticulated in the apical half; veins rather promi- 
nent, the lateral ones straight. Stipules adnate for about two- 
thirds of their length, ovate, abruptly acuminated; those which 
enclose the flower-heads enlarged. Flower-heads terminal and 
axillary, sessile, solitary, approximate, sometimes confluent, ovoid. 
Flowers sub-sessile. Calyx-tube bell-shaped, faintly 10-nerved, 
sub-glabrous, open at the throat; teeth lanceolate-acuminate, not 
spinescent, not auricled at the base, with a slender central nerve, 
all nearly equal, at length spreading-recurved as long as the calyx- 
tube. Corolla shorter than the calyx-teeth. Pod 2-seeded. Plant 
glabrous. 
On sandy and gravelly pastures and waste places. Rare. In 
the counties of Cornwall, Devon, Hants, Sussex, Kent, Suffolk, 
Norfolk; also in Wales. 
England. Annual. Early Summer. 
Stems prostrate, spreading in a circle, 1 to 7 inches long, often 
half-buried in the sand, the central one reduced to a sessile head of 
flowers. Leaves on stalks 11 to 2 inches long; leaflets } to } inch 
long. Stipules thin and membranous. Heads about j¢ inch across, 
generally so crowded as to conceal the stem, which they clothe 
from the base to the summit. Flowers lax, sub-sessile, + inch 
long, whitish; standard becoming scarious and slightly striate, 
but retaining its form much less distinctly than in T. glomeratum. 
Calyx-tube and teeth much less rigid than in the four preceding 
species. Pod enclosed in the calyx, containing 2 seeds. 
This plant is easily distinguishable from all the British Trefoils 
by its dense masses of flower-heads, which sometimes appear to 
be in spikes, from the separate heads actually touching each 
other, although each one lies in the axil of a separate leaf. These 
